In the SaxoWiki we explain types and terms in the field of fasteners for textiles.

A zipper consists of the following parts:
Non-separable zipper, labeled

Non separable

  1. Top tape extension
    • 1a. Filler cord
  2. Top stop
  3. Slider
  4. Slider pull tab
  5. Tape
  6. Chain width
  7. Bottom stop
  8. Bottom tape extension
  9. Tape width
  10. Insertion pin
  11. Retainer Box
  12. Tape reinforcement
Separable zipper, labeled

Separable zipper,
Open end (O/E) zipper

The end or bottom of a zipper is where the slider is located when the zipper is completely opened.
Bottom stop
The bottom stop stops the slider at the bottom of the zipper, so that the slider does not slide out at the bottom of the zipper chain.
Chain width
Zippers are not fine-mechanical precision parts, but must work for its dedicated purpose. This is probably why the German Institute for Standardization (DIN) classified the chain widths, which vary due to production, only roughly in the its standards.
In May 2016, the German Institute for Standardization replaced standards 3417 & 3418 and other zipper standards by the new standard DIN EN 16732. The previous zipper types RT0, RT10 etc., grouped according to chain width, were omitted. Instead, the new DIN standard obviously follows the British Standards BS 3084:2006 and groups zippers into performance codes A (ultra-light), B (light), C (medium), D (medium-heavy) and E (heavy). Since these descriptions do not specify chain widths, they do not explain the numbers for the width of zippers commonly used in Germany up to now. Therefore, we show the interested reader how the terms still widely used in Germany for zipper chain widths correspond to the old DIN standards.

So that we can distinguish the fine differences in our zipper range, we have our own size and type numbering, which is based on the DIN nomenclature valid until 2016, but differs in detail. Below we show how DIN standards classify zippers according to type & size, which numbering is common internationally and which numbering Saxotex uses. In case of doubt, please send us a sample of your zipper.

Classification according to DIN 3418
Plastic wire zip fasteners
Saxotex numberingOpti-lon
gauge of chain
in mm
Zip fastener
chain width
in mm, ca.
Sewn on
spiral chain
Woven in
spiral chain
3,6 to 4,8RT0#34Nr.0S0S40
4,8 to 5,5RT5#45Nr.5S50
5,6 to 6,8RT10#56Nr.10S10S60
#66,3Nr.10 2-way
6,9 to 7,5RT15#87,2Nr.20
7,6 to 8,8RT208,2Nr.22S20S80
8,8 to 12RT25#1010,5Nr.25
Classification according to DIN 3418
Plastic injection molded zip fasteners
gauge of chain
in mm
Zip fastener
chain width
in mm, ca.
3,6 to 4,8RT0#34,7D43VS
4,8 to 5,5RT5
5,5 to 6,8RT10#55,8D65VS
7,2 to 8,9RT20#87,8D88VS
8,6 to 12RT25#108,7D910VF
Why the DIN groups of gauge of chain
are not consistent is unknown.
Classification according to DIN 3417
Metal zip fasteners
chain width
in mm
Zip fastener
chain width
in mm, ca.
4,0 to 5,0RT5#34,5M0
5,5 to 6,4RT10#56M10
6,3 to 7,1RT157M15
7,0 to 8,0RT20#88M20
8,4 to _9,5RT25#109M25
Core spun yarn
Hook lock
... is a nowadays rarely used name for the small hooks, pins or thorns on semi-automatic sliders and pinlock sliders. For both types of slider, you have to actively fold down the slider pull tab so that the locking thorn hooks into the zipper chain and thus locks the slider at its position.
The slider closes and opens the zipper chain when moving it along the chain. According to their locking effect, there are 4 types of sliders:

... have no lock. Those will unfasten and moving on the zipper chain already when a low force acts on the slider pull tab or the slider body. Therefore, non lock sliders also move when the zipper chain is pulled apart and opens thereby. This is particularly desirable for handbags or inner jacket pockets. Because even if the zipper is only slightly open, you don't necessarily have to grab the slider pull tab to open further. Rather, it is sufficiently to widen the opening with one Finger or hand. Then the slider slides back and the bag opens.

slider No.0, nonlock, short tab Slider No.0 nonlock, long pull tab, nickel Nonlock sliders typically have a longer pull tab than other types of sliders. Saxotex calls this long tab. But there are also nonlock sliders with the shorter standard pull tab. Saxotex calls this short tab.

Externally, you can recognize non-lock sliders slider by the kind of attaching their pull tab. There is no cap, no planchette and also no spring. Instead the pull tab is attached at the sliderbody by a simple lug (long pull tab) or two claws (short pull tab).

Sliders without pull tab,such as those often used for bed linen, are always non locking.

... have a thorn inside. A small leaf spring in the slider automatically presses the thorn between the teeth of the closed zipper chain. As a result, the slider can not move unintentionally, except in the case of vibrations. If you pull on the pull tab of the slider, the thorn will be pulled out of the zipper chain and only then the slider can move. To ensure that the main zippers on jackets, trousers, skirts, dresses and shoes do not open unintentionally due to body movements, for such garments are always used automatic sliders.

Automatic slider with planchette Automatic slider with cap The spring and thorn mechanism of automatic sliders is hidden either under a cap or under a planchette.

... only lock when the pull tab is folded flat down. Therefore those sliders are also called flat-lock sliders. A further name is YG slider. You have to overcome a spring force to fold the pull tab up and thereby loosen the lock. Compared to standard automatic sliders, semi automatic slider are more ruggedized and have a significantly stronger spring, which reliably prevents the slider from sliding unintentionally even during vibrations.
No.10 flat lock semi automatic YG slider, whiteslider M0, semi Automatic, brassThe disadvantages are that

  • you have to fold the pull tab down manually to lock,
  • they are usually more expensive,
  • they do not look very elegant due to design,
  • they are rarely produced with decorative pull tabs.

Pin-Lock slider ... lock by means of prongs or small pins against unintentionally sliding. Prongs or pins are cast on the down side of the slider pull tab. Therefore, these locks only press into the zipper chain when the pull tab of the slider is folded down. In contrast to semi-automatic sliders, however, the slider pull tab in the folded down position does not hold by spring force, but only by gravity. Just you move the zipper unfavorably, the slider pull tab easily fold away from this locking position, allowing the slider to slip unintentionally. Because of this uncertain locking effect, pinlock sliders should only be used if, for example, in the final product a strip of fabric overlaps the slider (concealed sewn zipper) and thus holds the zipper slider pull tab in the folded down position.

Pin lock sliders are very cheaply produced due to their simple design However, since they only lock insecurely, but also slide freely only limited, they are rarely used these days, for example in home textiles such as cases for pillows and bedding.

On the tape the single teeth or the spiral chain are attached. Commonly the tapes are made of woven polyester, less often cotton or polyamide.
Tape extension
At the top and at the bottom of a zipper the tapes are longer than the zipper chain, so that you can sew the zipper better and more stable into the surrounding material.
Tape width
The width of the zipper tape is unimportant for most uses of zippers. For some products, however, particularly wide or narrow zipper tapes are necessary. If you want to order zippers with special tape widths, please always measure the width of a single tape.
The beginning or top of a zipper is where the slider is when the zipper is completely closed.
Top stop
The top stop stops the slider at the top of the zipper, so that the slider does not slide out at the top of the zipper chain. Usually zip fasteners have two top stops. Non-separable, O-shaped zippers as well as double open end zippers have no
Zipper sliders have a wedge, also called diamond, inside. This wedge separates the coupling elements of the two sides of the fastening chain when you open the zipper.
Zipper band
See tape

Below we show the most common functional types of zippers

Zipper, closed end

Not separable

Zipper, closed end, O-shaped

non separable, O-shaped

Zipper, closed end, X-shape

non-separable, X-shape

Zipper, separable


Zipper, double separable

separable on both sides (double open end)

Zipper, separable, X-shape

separable, 2-way, X-shape

Zipper, open end with quick release system

separable, with quick release system

Zipper, open end with swivel-separable element

open end, with swivel-separable element

Zipper, endless by-the-meter

endless by-the-yard