In this article
O type zipper
Both ends have bottom stops and the sliders meet head to head. The zipper is closed when the sliders touch. The opening between them looks like an "O". It is common on bags and luggage, where the sliders can be locked together.
X type zipper
Both ends have top stops and the sliders sit back to back. The zipper is closed when the sliders are farthest apart. It opens from both ends and stays closed in the middle, like an "X". It is used on bags, luggage and sleeping bags.
| O type | X type | |
|---|---|---|
| Sliders | Head to head | Back to back |
| Closed when | Sliders touch | Sliders farthest apart |
| Ends | Bottom stops | Top stops |
| Opening | In the middle | At the ends |
Which should you choose?
- Choose O type to open the zipper from the middle.
- Choose X type to open it from both ends.
Watch the terminology
"Two-way" and "reversible" are not used consistently across suppliers. The clearest wording is "two sliders, O type" or "two sliders, X type".
How does the difference feel in use?
On an O type, moving the two sliders apart creates an opening in the middle, so you can reach in at any point. On an X type, moving the sliders towards the middle opens the ends, giving access from both.
Which suits what?
- Luggage and lockable bags: O type sliders sit side by side when closed, so they are easy to lock together.
- Long bags and sleeping bags: X type works where both ends should open.
- Garment bags: Choose according to whether you need access from the top or bottom.
Is it the same as a two-way open-end zipper?
No. A two-way open-end zipper on a coat separates fully, with a pin and box at the bottom. X and O types are closed at both ends, so the sides do not separate.
How to specify it
Codes and words vary between suppliers, so write it out clearly. For example: "Size 8 coil, closed at both ends, two sliders, O type, non-lock, 60 cm." This reduces confusion even when the maker's code differs.
What to check on a sample
- Where the sliders sit when fully closed
- The alignment of slider holes if a lock will be used
- How smoothly the slider runs around corners
Frequently asked questions
What is the difference between X and O type zippers?
An O type is closed when the sliders touch; an X type is closed when they are farthest apart.
Which zipper does luggage use?
Usually a two-way coil or molded plastic zipper. O type suits use with a lock.
Is a two-way zipper the same as an open-end zipper?
No. An open-end zipper's sides separate, while X and O types are closed at both ends.
Which type do sleeping bags use?
X type and two-way models with reversible sliders are common.
