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 how much does the average DIYer really know about zippers? We're here to help. In today's blog, we're going to take the mystery out of zippers by explaining, in detail, every part of a zipper, its function, and if that part can be replaced or repaired.

First, let's talk about zipper quality. At Sailrite®, we only carry YKK® brand zippers — the best in the world. In much the same way that your 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. You can depend on YKK zippers to function correctly and consistently, time after time and year after year. The reliability of YKK zippers is why it is the only brand of zippers and zipper finishing items we stock.

Zipper Parts Explained

Parts of a zipper labeled and explained.

Top Stop: The top stops are positioned at the top of the teeth on both sides and prevent the slider from pulling off of the teeth. On a Finished Zipper, the top stops are already present. You can add top stops to a Continuous Zipper Chain.

Shop for Zipper Stops.

Tape: This is the fabric part of the zipper. The teeth are molded onto the zipper tape. This is the portion of the zipper that will be sewn into your fabric application. If the teeth have somehow been ripped apart from the tape, there is no fix for that. You'll have to replace the zipper.

Teeth: The interlocking teeth are molded or sewn to the zipper tape on both sides. Connecting the teeth together using the slider is what closes the zipper. There are three different types of zipper teeth: VISLON®, Coil and Metal.

A close-up of the three types of zipper teeth.

Slider/Pull: The slider is connected to the teeth. This component zips the teeth apart or closed. The pull is attached to the slider and this is the portion of the zipper that you pull to open and close the zipper. A Finished Zipper will have a slider and pull installed, but a Continuous Zipper Chain will not. You will need to purchase a slider for a Continuous Chain. Double-pull sliders have a zipper pull on both sides of the slider and allow the zipper to be opened and closed from either side.

Shop for Finished Zippers.

Shop for Continuous Zipper Chains.

There are two types of sliders: locking and non-locking. A locking zipper slider will only move when it is grasped and pulled. A non-locking slider will move along the zipper chain if any part of the zipper slider is pulled or if the zipper teeth are grasped and pulled apart.

Shop for Zipper Sliders and Pulls.

Starter Box/Retaining Box: Only found on a separating or "jacket style" Finished Zipper, the starter box is located at the bottom of the zipper on one side of the zipper tape, opposite the insertion pin. The starter box's function is to correctly align the insertion pin in order to join the zipper halves and close the zipper. The starter box cannot be added to a Continuous Zipper.

Insertion Pin: Only found on a separating or "jacket style" Finished Zipper, the insertion pin is located at the bottom of the zipper on one side of the zipper tape, opposite the starter box. The insertion pin is inserted through the slider and connects to the starter box, which enables the zipper to be closed via the slider.

If your starter box or insertion pin is broken or damaged, unfortunately, these parts cannot be replaced because they are welded to the zipper tape. You'll need to replace the zipper.

More Zipper Resources

If you'd like to learn more about zippers, we have several informative zipper blogs. "Choosing the Right Zipper" (#300049XHT) will help you find the correct size and style of zipper for your application. Are you not sure if you need a locking or non-locking zipper, or a Finished or Continuous Zipper Chain? This blog tells you everything you need to know. Do you have a damaged or broken zipper slider? "Choosing a Replacement Zipper Slider" (#300081XHT) will give you all the information you need to know to purchase a replacement zipper slider.