Anatomy of a Zipper

Item # X-HT-300496

So many DIY projects involve zippers. Cushions, garments, boat enclosures, removable window installations … the list goes on and on. But do you know what each part of a zipper is called and what it does?

If not, don’t worry — we're here to help. This blog will take the mystery out of this important notion by explaining every part of a zipper and its function. You’ll also learn which zipper components can be replaced when they wear out or break, and when you’ll have to replace the whole zipper.

But first, let's talk about zipper quality. In the same way that thread can be the weakest part of your sewing assembly, a cheap, poor-quality zipper is likely to malfunction and cause you nothing but stress and frustration. Quality matters when you want to sew something that looks good and lasts for years. That’s why we stock two high-quality zipper brands at Sailrite®: Lenzip® and YKK®. You can depend on zippers from these brands to function correctly and consistently, time after time and year after year.

Zipper Parts Explained

Now let’s jump into our discussion about the parts of a zipper. Each component plays an important role in building a smooth, long-lasting zipper. Understanding the role of each part will help you get the most life out of the zippers you use in your DIYs.

Anatomy Zipper Parts 2

Top Stop: Top stops prevent the zipper slider from pulling off the top end of a zipper. Two stops are preinstalled on a separating zipper — one on each side of the tape. You can add top stops to a continuous zipper chain as needed, since stops don’t come preinstalled on continuous chain. In most cases, you can replace a broken or missing top stop without having to replace the whole zipper.

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Slider & Pull: This two-in-one component is what interlocks or separates the zipper teeth. The slider is installed on the teeth, and a mechanism inside the slider laces or unlaces the teeth when the slider moves. The pull is the tab you use to move the slider to open or close the zipper.

A slider and pull come preinstalled on separating zippers, but not on continuous zipper chain. You will need to purchase a compatible slider/pull for a continuous chain and install it yourself. (For example, a #5 slider for molded tooth chain will only work with a #5 molded tooth chain. A #10 coil chain will only work with a #10 slider for coil chain.) Choose from a locking or non-locking slider with a single or double pull. For more information about sliders, read our blog "Choosing a Replacement Zipper Slider" (#300081XHT).

You can usually replace a broken or missing slider and pull on a separating zipper. But on a zipper with one or both ends stopped or sewn shut, you may have to replace the whole zipper if removing a stop or resewing the zipper aren’t feasible options.

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Teeth: The interlocking teeth are what keep a zipper closed. Depending on the material your zipper teeth are made of, they will be molded, sewn or crimped to the tape on both sides.

Zipper teeth are available in three different types: molded tooth, coil and metal. They’re all made of different materials and have different recommended uses. (See our blog, "Choosing the Right Zipper" (#300049XHT), for more on these materials.) It’s impossible to repair or replace a broken or missing zipper tooth. The whole zipper would have to be replaced.

Anatomy Zipper Parts 3
A close-up of the three types of zipper teeth.

Tape: This is the fabric part of the zipper, which you will sew into your project. The tape holds the zipper teeth. There is no way to fix zipper tape that is missing needed teeth. You'd have to replace the whole zipper.

Starter Box: Only found on fully separating or "jacket-style" finished zippers, the starter box is located at the bottom of the zipper. There is only one starter box per zipper, and it’s on one side of the tape opposite the insertion pin. The starter box correctly aligns and holds the insertion pin so the slider can join the zipper teeth. A starter box cannot be added to a continuous zipper chain.

Insertion Pin: Only found on fully separating or "jacket-style" finished zippers, the insertion pin is located at the bottom of the zipper. There is only one insertion pin per zipper, and it’s on one side of the tape opposite the starter box. The insertion pin is inserted through the slider and into to the starter box, which enables the slider to close both halves of the zipper. Like a starter box, an insertion pin cannot be added to a continuous zipper chain.

Missing or broken starter boxes and insertion pins cannot be replaced because they are fused to the zipper tape. You'll need to replace the whole zipper if either component gets lost or breaks.

More Zipper Resources

Sailrite is your go-to resource for all things zippers! We stock a full and diverse inventory of zippers and components: finished zippers, continuous zipper chain lengths, zipper pulls and sliders, and zipper top and bottom stops. We’re proud to stock both Lenzip and YKK brand zipper components. Both brands are giants in the industry, known for quality parts that last. Our Lenzip supply is by far our most robust zipper offering, with a wide variety of finished, separating and continuous zipper styles, colors and sizes, as well as sliders and pulls in a multitude of colors and styles to choose from. Think of Sailrite as your trusted zipper supplier.

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Shop for Continuous Zipper Chains

If you'd like to learn more about zippers, check out our other informative blogs on this notion. "Choosing the Right Zipper" (#300049XHT) will help you find the correct size and style of zipper for your application. If you have a damaged or broken zipper slider, "Choosing a Replacement Zipper Slider" (#300081XHT) will give you all the information you need to purchase a replacement.

Still have questions? Our highly trained customer service team is ready to assist you. Just call, email or online chat with us to get help with all your zipper questions.

This blog was updated in February 2023 to reflect updated inventory.