Zip Fastener

Zip Fastener Market Outlook

As of 2023, the global zip fastener market is valued at approximately $4.5 billion, with a projected compound annual growth rate (CAGR) of 6.5% from 2025 to 2035. The increasing demand for zip fasteners in various industries, such as apparel, automotive, and home furnishings, is primarily driving this growth. Additionally, the rise of e-commerce and online retailing has significantly expanded the distribution channels for zip fasteners, making them more accessible to consumers worldwide. The evolving fashion trends and the continuous innovation in materials and designs further contribute to the market's expansion. Moreover, the growing emphasis on functionality and aesthetics in products that utilize zip fasteners is expected to bolster their demand in the coming years.

Growth Factor of the Market

The growth of the zip fastener market is influenced by several key factors that highlight the changing consumer preferences and advancements in manufacturing technologies. One significant factor is the increasing consumer inclination towards lightweight and durable fastening solutions, which have become crucial in sectors like fashion apparel and sportswear. Innovations such as water-resistant and invisible zip fasteners are also gaining traction, appealing to both manufacturers and consumers who prioritize quality and performance. Furthermore, the expansion of the automotive industry globally is driving the demand for specialized zip fasteners that can withstand various environmental conditions. The growing trend of customization in fashion and accessories promotes the use of unique and branded zip fasteners, further propelling market growth. In addition, sustainability efforts among consumers and manufacturers have led to an increased interest in eco-friendly materials, positively impacting the market dynamics.

Key Highlights of the Market

• The global zip fastener market is projected to reach $8 billion by 2035.
• Online retail platforms are becoming the primary distribution channel for zip fasteners.
• North America is expected to hold a significant market share, driven by the apparel industry.
• Plastic zip fasteners are anticipated to witness the highest growth rate due to their lightweight properties.
• Technological advancements in fastener designs are enhancing product functionality and aesthetics.

By Product Type

Metal Zip Fasteners:

Metal zip fasteners are widely recognized for their strength, durability, and classic aesthetic appeal. Used predominantly in high-end fashion and heavy-duty applications, these fasteners are typically made from materials such as brass, aluminum, or stainless steel. Their capacity to withstand wear and tear makes them ideal for jackets, bags, and outdoor gear. The premium look and feel of metal zip fasteners enhance the overall design of garments and accessories, adding a touch of elegance. As consumers increasingly seek quality products that combine functionality with style, the demand for metal zip fasteners has shown a steady rise, especially in luxury and performance-oriented markets.

Plastic Zip Fasteners:

Plastic zip fasteners stand out for their lightweight nature and versatility, making them suitable for a variety of applications, from casual apparel to children's clothing. Manufacturers favor these fasteners due to their cost-effectiveness and ability to be produced in various colors and designs, allowing for creative expression in fashion. The trend towards sustainable fashion has also led to the development of biodegradable plastic zip fasteners, appealing to environmentally conscious consumers. The ease of manufacturing and flexibility in design further contribute to the growing preference for plastic zip fasteners, especially in the fast-fashion sector where rapid product turnover is essential.

Nylon Zip Fasteners:

Nylon zip fasteners are characterized by their resilience and flexibility, making them a popular choice for activewear and sports equipment. Known for their resistance to moisture and abrasion, these fasteners are ideal for outdoor applications and garments exposed to harsh conditions. The lightweight nature of nylon zip fasteners also contributes to the comfort and performance of the end product, particularly in athletic gear. As the global fitness trend continues to grow, the demand for nylon zip fasteners is expected to increase, cementing their status as a vital component within the sports and outdoor apparel market.

Invisible Zip Fasteners:

Invisible zip fasteners offer a seamless fastening solution that enhances the overall aesthetic of garments by concealing the zip within the fabric. This type of fastener is particularly favored in formalwear, evening dresses, and tailored clothing where a clean finish is paramount. Designers appreciate the ability of invisible zip fasteners to maintain the garment's silhouette while providing functionality. As fashion trends evolve towards minimalism and understated elegance, the demand for invisible zip fasteners is anticipated to grow, particularly among high-end fashion brands seeking to create luxurious yet practical designs.

Water-Resistant Zip Fasteners:

Water-resistant zip fasteners are engineered to provide an additional layer of protection against the elements, making them an essential component in outdoor apparel, luggage, and sports gear. With outdoor activities gaining popularity, the need for reliable water-resistant solutions has surged. These specialized fasteners are designed to prevent water infiltration while maintaining ease of use, which is critical for consumers engaging in outdoor adventures. The increasing focus on functionality and performance in product design will likely fuel the growth of water-resistant zip fasteners in both the sporting goods and fashion industries.

By Application

Apparel:

The apparel segment is one of the largest consumers of zip fasteners, employing them across a wide range of clothing types, from casual wear to formal attire. The demand for innovative fastening solutions that enhance both the functionality and aesthetic appeal of garments drives the growth of this sector. Fashion designers increasingly utilize various types of zip fasteners to create unique designs that cater to diverse consumer preferences. Additionally, the rapid evolution of fashion trends requires manufacturers to adapt quickly, leading to a constant need for new and customizable zip fasteners that align with contemporary styles. As the global fashion industry continues to thrive, the apparel application will remain a significant driver of zip fastener sales.

Luggage and Bags:

Zip fasteners play a crucial role in the luggage and bags segment, providing both security and ease of access to the contents within. The growing travel and tourism industry has led to an increase in demand for durable and reliable luggage, where high-quality zip fasteners are essential for ensuring longevity. Manufacturers are focusing on producing zippers that can withstand heavy use and environmental stresses while maintaining smooth functionality. Additionally, innovations in design, such as anti-theft features and water-resistant zippers, are becoming popular, enhancing the overall value proposition of luggage products. As travel continues to rebound post-pandemic, the luggage and bags application is poised for substantial growth.

Automotive:

The automotive application for zip fasteners encompasses a range of components, from upholstery to storage solutions within vehicles. Zip fasteners provide an effective means of securing various parts while allowing for easy access and maintenance. As automotive manufacturers strive to improve the quality and design of vehicles, there is a growing emphasis on using durable and aesthetically pleasing fasteners. The rise of electric vehicles and advancements in automotive technology further promote the need for innovative fastening solutions that can meet specific performance standards. This segment is expected to see significant growth as the automotive industry seeks to enhance user experience and functionality within vehicles.

Home Furnishings:

In the home furnishings sector, zip fasteners are commonly utilized in products such as cushions, curtains, and bedding. They provide convenience in terms of maintenance and aesthetics, allowing consumers to easily remove covers for washing or replacement. The trend towards customization in home decor has also increased the demand for zip fasteners, as consumers seek to create personalized living spaces. Moreover, with the rise of e-commerce, manufacturers are targeting online platforms to reach consumers looking for unique home furnishing items. As the home furnishings market continues to grow, the use of zip fasteners will become increasingly important for both functionality and design.

Others:

The "Others" category encompasses various applications of zip fasteners beyond the primary sectors of apparel, luggage, automotive, and home furnishings. This includes industries such as medical devices, sports equipment, and specialized industrial applications. The versatility of zip fasteners allows them to be employed in myriad products that require secure and reliable fastening solutions. As technology advances and industries evolve, the demand for zip fasteners in these niche markets is expected to grow, tapping into new opportunities for innovation and product development.

By Distribution Channel

Online Retailers:

Online retailers have emerged as a leading distribution channel for zip fasteners, offering consumers a wide variety of products at competitive prices. The convenience of shopping from home, coupled with extensive product catalogs, has driven a significant increase in online sales for zip fasteners. E-commerce platforms allow consumers to access various brands and product types, facilitating easy comparisons. Additionally, the rise of digital marketing strategies has enabled manufacturers to effectively target their audience and promote their products online. As consumer behavior continues to shift towards online shopping, this distribution channel is expected to see sustained growth in the coming years.

Specialty Stores:

Specialty stores cater to specific consumer needs and preferences, making them a vital distribution channel for zip fasteners. These stores often focus on quality, offering a curated selection of products that appeal to niche markets, such as high-end fashion or outdoor gear. Consumers visiting specialty stores are typically seeking expert advice and unique products, which makes this distribution channel invaluable. The personalized shopping experience and knowledgeable staff help build customer loyalty, encouraging repeat purchases. As the demand for specialized products continues to rise, specialty stores will play an essential role in the zip fastener market.

Department Stores:

Department stores serve as a traditional distribution channel for zip fasteners, providing consumers with a one-stop shopping experience for various household needs. These stores typically offer a range of products, including clothing, accessories, and home goods, making zip fasteners a complementary category within their inventory. The visibility and accessibility of zip fasteners in department stores can drive impulse purchases, especially among consumers looking for quick solutions. With the continued integration of e-commerce into their business models, department stores are adapting to changing consumer preferences while maintaining their importance in the retail landscape.

Discount Stores:

Discount stores provide a cost-effective option for consumers seeking affordable zip fasteners without compromising on quality. These stores often target budget-conscious shoppers, offering a selection of products at lower price points. The growing trend of frugal consumerism has led to increased foot traffic in discount stores, resulting in higher sales volumes for zip fasteners. As the demand for economical solutions rises, discount stores are likely to continue expanding their offerings, providing consumers with a significant source of zip fasteners at competitive prices.

Others:

The "Others" category includes various unconventional distribution channels, such as craft stores, hardware stores, and wholesale outlets. These channels often cater to specific audiences, such as DIY enthusiasts or professional seamstresses, offering unique types of zip fasteners tailored to particular projects. By diversifying the distribution landscape, these channels help increase the availability and accessibility of zip fasteners, catering to the diverse preferences of consumers. As the demand for creative and specialized applications continues to grow, these alternative distribution channels will play an increasingly important role in the overall market.

By Material Type

Brass:

Brass zip fasteners are known for their durability and classic aesthetic, often utilized in high-end fashion and functional applications. The corrosion-resistant properties of brass make it an ideal material for zip fasteners that need to withstand wear over time. Manufacturers appreciate the strength and reliability of brass zippers, which are critical in products like jackets and bags that endure frequent use. Furthermore, brass is easily customizable in terms of color and finish, allowing brands to align their products with current fashion trends. As consumer demand for quality products continues to rise, the use of brass zip fasteners is expected to remain strong.

Aluminum:

Aluminum zip fasteners are increasingly popular due to their lightweight nature and resistance to corrosion. These fasteners are commonly used in both fashion and industrial applications where weight is a critical factor. The strength-to-weight ratio of aluminum makes it an attractive option for manufacturers seeking to create durable yet functional products. Additionally, aluminum can be anodized for added aesthetic appeal and protection, further enhancing its desirability in the fashion industry. As trends shift towards lightweight and durable materials, the adoption of aluminum zip fasteners is likely to grow.

Stainless Steel:

Stainless steel zip fasteners offer exceptional strength and resistance to corrosion, making them suitable for heavy-duty applications. They are frequently used in environments where exposure to moisture and harsh conditions is prevalent, such as in outdoor gear and automotive components. The longevity and reliability of stainless steel fasteners appeal to manufacturers focused on producing high-quality, durable products. As markets increasingly prioritize functionality and performance, the demand for stainless steel zip fasteners is expected to rise, particularly in industries where safety and durability are paramount.

Plastic:

Plastic zip fasteners are highly versatile, offering a lightweight and cost-effective solution for various applications. They are commonly found in casual apparel, accessories, and fast-fashion products, where affordability and design flexibility are crucial. The ability to produce plastic zip fasteners in a myriad of colors and styles allows manufacturers to cater to diverse consumer preferences. Additionally, advances in biodegradable plastic technology are addressing environmental concerns, making plastic zip fasteners an attractive option for eco-conscious brands. As sustainability becomes increasingly important in consumer purchasing decisions, the demand for plastic zip fasteners is expected to remain robust.

Others:

The "Others" category includes a variety of materials used in the production of zip fasteners, such as rubber and silicone. These materials are often employed in specialized applications where traditional materials may not suffice. For example, rubber zip fasteners may be found in products designed for aquatic use, offering flexibility and water resistance. Similarly, silicone fasteners can provide unique features such as stretchability and comfort. As manufacturers continue to innovate and explore new materials, the "Others" segment is likely to see growth as niche applications emerge, driving further diversification within the zip fastener market.

By Region

North America represents a significant share of the global zip fastener market, driven largely by the robust apparel and automotive industries. The region's emphasis on quality and performance in manufacturing ensures a high demand for advanced fastening solutions. In 2022, the North American zip fastener market was valued at approximately $1.6 billion and is projected to grow at a CAGR of 6% through 2035. The growing consumer interest in sustainable products is also influencing market dynamics, leading manufacturers to adapt their offerings to meet eco-friendly standards.

Europe follows closely behind North America in terms of market share, largely due to the established fashion industry and increasing consumer demand for innovative home furnishing solutions. The European zip fastener market was valued at around $1.4 billion in 2022, with expectations of continued expansion as manufacturers embrace new materials and designs. The region's focus on sustainability and technological advancements will likely drive significant growth in the coming years. Meanwhile, the Asia Pacific region is also emerging as a potential growth hub, with a rapidly expanding manufacturing sector and increasing consumer preferences for affordable yet high-quality products.

Opportunities

The zip fastener market presents numerous opportunities for growth, particularly in the realm of technological innovation. As manufacturers invest in research and development, they are discovering new materials and designs that enhance the functionality and appeal of zip fasteners. Innovations such as self-locking mechanisms, water-resistant coatings, and customizable colors are attracting a wider range of consumers, from fashion designers to outdoor enthusiasts. Additionally, the rising trend of sustainable fashion is prompting manufacturers to explore eco-friendly materials and production methods, positioning themselves favorably in the eyes of environmentally conscious consumers. This shift towards sustainability not only meets current market demands but also opens new avenues for product development, creating a win-win scenario for businesses and consumers alike.

Moreover, the expansion of e-commerce platforms provides significant growth opportunities for the zip fastener market. With more consumers opting to shop online, manufacturers and retailers can broaden their reach, tapping into previously underserved markets. The ability to showcase a diverse range of products digitally allows for increased consumer engagement and brand loyalty. Furthermore, collaborations between fashion brands and zip fastener manufacturers can lead to unique product offerings that drive sales and enhance brand visibility. By embracing these trends and opportunities, stakeholders in the zip fastener market can position themselves for long-term success and profitability.

Threats

Despite the numerous opportunities for growth in the zip fastener market, several threats could potentially hinder progress. One major concern is the volatility of raw material prices, which can significantly impact manufacturing costs and profit margins. Fluctuations in prices for materials such as brass, aluminum, and nylon may lead to uncertainty for manufacturers and disrupt supply chains. This unpredictability could force companies to make difficult decisions regarding pricing strategies and product offerings, ultimately affecting their competitiveness in the market. Additionally, the rise of alternative fastening solutions, such as magnetic closures or hook-and-loop fasteners, poses a challenge to the traditional zip fastener market. As consumer preferences evolve, manufacturers must adapt and innovate to retain market share and relevance.

Moreover, the increasing focus on sustainability has led to heightened scrutiny of manufacturing practices. Companies that fail to adopt eco-friendly production methods may face backlash from consumers and regulatory bodies, potentially damaging their reputation and market standing. The growing trend of circular economy practices emphasizes the need for manufacturers to consider the entire lifecycle of their products, from sourcing materials to end-of-life disposal. Failure to address these issues could result in lost business opportunities and reduced customer loyalty. As such, stakeholders must remain vigilant and responsive to both market trends and potential threats to navigate the challenges ahead.

Competitor Outlook

• YKK Group
• Aurora Specialty
• Coats Group
• Ideal Fasteners
• Riri Group
• SBS Zipper
• Talon International
• Zipfast
• KCC Zipper
• HSD Zippers
• YKK AP
• Zipper & Zipper
• Teijin Limited
• Hexcel Corporation
• Vortex Zippers

The competitive landscape of the zip fastener market comprises a diverse group of companies that vary in size, product offerings, and geographical presence. Market leaders such as YKK Group and Coats Group dominate the industry, leveraging their extensive experience, brand recognition, and innovative capabilities to maintain a competitive edge. These companies invest heavily in research and development to create cutting-edge fasteners that meet the evolving demands of consumers and industries alike. Additionally, they have established robust supply chains and distribution networks, enabling them to efficiently deliver products to various markets worldwide.

Emerging players within the zip fastener market are increasingly focused on niche applications and sustainability. Companies like SBS Zipper and Riri Group are carving out their market share by offering specialized products tailored to specific industries, such as luxury fashion and outdoor gear. Their commitment to sustainable practices and eco-friendly materials resonates with a growing segment of environmentally conscious consumers. As competition intensifies, these emerging players are expected to foster innovation and contribute to the overall growth of the zip fastener market.

Furthermore, collaborations between manufacturers and fashion brands are becoming increasingly common as companies seek to enhance their product offerings and reach new customers. These partnerships often lead to the creation of unique, custom zip fasteners that align with brand aesthetics and target specific markets. By fostering collaboration and innovation, the zip fastener industry can capitalize on emerging trends and consumer demands, ensuring continued growth and success in the years to come.

• 1 Appendix

  • 1.1 List of Tables
  • 1.2 List of Figures

• 2 Introduction

  • 2.1 Market Definition
  • 2.2 Scope of the Report
  • 2.3 Study Assumptions
  • 2.4 Base Currency & Forecast Periods

• 3 Market Dynamics

  • 3.1 Market Growth Factors
  • 3.2 Economic & Global Events
  • 3.3 Innovation Trends
  • 3.4 Supply Chain Analysis

• 4 Consumer Behavior

  • 4.1 Market Trends
  • 4.2 Pricing Analysis
  • 4.3 Buyer Insights

• 5 Key Player Profiles

  • 5.1 YKK AP
    • 5.1.1 Business Overview
    • 5.1.2 Products & Services
    • 5.1.3 Financials
    • 5.1.4 Recent Developments
    • 5.1.5 SWOT Analysis
  • 5.2 Zipfast
    • 5.2.1 Business Overview
    • 5.2.2 Products & Services
    • 5.2.3 Financials
    • 5.2.4 Recent Developments
    • 5.2.5 SWOT Analysis
  • 5.3 YKK Group
    • 5.3.1 Business Overview
    • 5.3.2 Products & Services
    • 5.3.3 Financials
    • 5.3.4 Recent Developments
    • 5.3.5 SWOT Analysis
  • 5.4 KCC Zipper
    • 5.4.1 Business Overview
    • 5.4.2 Products & Services
    • 5.4.3 Financials
    • 5.4.4 Recent Developments
    • 5.4.5 SWOT Analysis
  • 5.5 Riri Group
    • 5.5.1 Business Overview
    • 5.5.2 Products & Services
    • 5.5.3 Financials
    • 5.5.4 Recent Developments
    • 5.5.5 SWOT Analysis
  • 5.6 SBS Zipper
    • 5.6.1 Business Overview
    • 5.6.2 Products & Services
    • 5.6.3 Financials
    • 5.6.4 Recent Developments
    • 5.6.5 SWOT Analysis
  • 5.7 Coats Group
    • 5.7.1 Business Overview
    • 5.7.2 Products & Services
    • 5.7.3 Financials
    • 5.7.4 Recent Developments
    • 5.7.5 SWOT Analysis
  • 5.8 HSD Zippers
    • 5.8.1 Business Overview
    • 5.8.2 Products & Services
    • 5.8.3 Financials
    • 5.8.4 Recent Developments
    • 5.8.5 SWOT Analysis
  • 5.9 Teijin Limited
    • 5.9.1 Business Overview
    • 5.9.2 Products & Services
    • 5.9.3 Financials
    • 5.9.4 Recent Developments
    • 5.9.5 SWOT Analysis
  • 5.10 Vortex Zippers
    • 5.10.1 Business Overview
    • 5.10.2 Products & Services
    • 5.10.3 Financials
    • 5.10.4 Recent Developments
    • 5.10.5 SWOT Analysis
  • 5.11 Ideal Fasteners
    • 5.11.1 Business Overview
    • 5.11.2 Products & Services
    • 5.11.3 Financials
    • 5.11.4 Recent Developments
    • 5.11.5 SWOT Analysis
  • 5.12 Zipper & Zipper
    • 5.12.1 Business Overview
    • 5.12.2 Products & Services
    • 5.12.3 Financials
    • 5.12.4 Recent Developments
    • 5.12.5 SWOT Analysis
  • 5.13 Aurora Specialty
    • 5.13.1 Business Overview
    • 5.13.2 Products & Services
    • 5.13.3 Financials
    • 5.13.4 Recent Developments
    • 5.13.5 SWOT Analysis
  • 5.14 Hexcel Corporation
    • 5.14.1 Business Overview
    • 5.14.2 Products & Services
    • 5.14.3 Financials
    • 5.14.4 Recent Developments
    • 5.14.5 SWOT Analysis
  • 5.15 Talon International
    • 5.15.1 Business Overview
    • 5.15.2 Products & Services
    • 5.15.3 Financials
    • 5.15.4 Recent Developments
    • 5.15.5 SWOT Analysis

• 6 Market Segmentation

  • 6.1 Zip Fastener Market, By Application
    • 6.1.1 Apparel
    • 6.1.2 Luggage and Bags
    • 6.1.3 Automotive
    • 6.1.4 Home Furnishings
    • 6.1.5 Others
  • 6.2 Zip Fastener Market, By Product Type
    • 6.2.1 Metal Zip Fasteners
    • 6.2.2 Plastic Zip Fasteners
    • 6.2.3 Nylon Zip Fasteners
    • 6.2.4 Invisible Zip Fasteners
    • 6.2.5 Water-Resistant Zip Fasteners
  • 6.3 Zip Fastener Market, By Material Type
    • 6.3.1 Brass
    • 6.3.2 Aluminum
    • 6.3.3 Stainless Steel
    • 6.3.4 Plastic
    • 6.3.5 Others
  • 6.4 Zip Fastener Market, By Distribution Channel
    • 6.4.1 Online Retailers
    • 6.4.2 Specialty Stores
    • 6.4.3 Department Stores
    • 6.4.4 Discount Stores
    • 6.4.5 Others

• 7 Competitive Analysis

  • 7.1 Key Player Comparison
  • 7.2 Market Share Analysis
  • 7.3 Investment Trends
  • 7.4 SWOT Analysis

• 8 Research Methodology

  • 8.1 Analysis Design
  • 8.2 Research Phases
  • 8.3 Study Timeline

• 9 Future Market Outlook

  • 9.1 Growth Forecast
  • 9.2 Market Evolution

• 10 Geographical Overview

  • 10.1 Europe - Market Analysis
    • 10.1.1 By Country
      • 10.1.1.1 UK
      • 10.1.1.2 France
      • 10.1.1.3 Germany
      • 10.1.1.4 Spain
      • 10.1.1.5 Italy
  • 10.2 Zip Fastener Market by Region
  • 10.3 Asia Pacific - Market Analysis
    • 10.3.1 By Country
      • 10.3.1.1 India
      • 10.3.1.2 China
      • 10.3.1.3 Japan
      • 10.3.1.4 South Korea
  • 10.4 Latin America - Market Analysis
    • 10.4.1 By Country
      • 10.4.1.1 Brazil
      • 10.4.1.2 Argentina
      • 10.4.1.3 Mexico
  • 10.5 North America - Market Analysis
    • 10.5.1 By Country
      • 10.5.1.1 USA
      • 10.5.1.2 Canada
  • 10.6 Middle East & Africa - Market Analysis
    • 10.6.1 By Country
      • 10.6.1.1 Middle East
      • 10.6.1.2 Africa

• 11 Global Economic Factors

  • 11.1 Inflation Impact
  • 11.2 Trade Policies

• 12 Technology & Innovation

  • 12.1 Emerging Technologies
  • 12.2 AI & Digital Trends
  • 12.3 Patent Research

• 13 Investment & Market Growth

  • 13.1 Funding Trends
  • 13.2 Future Market Projections

• 14 Market Overview & Key Insights

  • 14.1 Executive Summary
  • 14.2 Key Trends
  • 14.3 Market Challenges
  • 14.4 Regulatory Landscape

Segments Analyzed in the Report

The global Zip Fastener market is categorized based on

By Product Type

• Metal Zip Fasteners
• Plastic Zip Fasteners
• Nylon Zip Fasteners
• Invisible Zip Fasteners
• Water-Resistant Zip Fasteners

By Application

• Apparel
• Luggage and Bags
• Automotive
• Home Furnishings
• Others

By Distribution Channel

• Online Retailers
• Specialty Stores
• Department Stores
• Discount Stores
• Others

By Material Type

• Brass
• Aluminum
• Stainless Steel
• Plastic
• Others

By Region

• North America
• Europe
• Asia Pacific
• Latin America
• Middle East & Africa

Key Players

• YKK Group
• Aurora Specialty
• Coats Group
• Ideal Fasteners
• Riri Group
• SBS Zipper
• Talon International
• Zipfast
• KCC Zipper
• HSD Zippers
• YKK AP
• Zipper & Zipper
• Teijin Limited
• Hexcel Corporation
• Vortex Zippers