Three zipper types appear in every product category: open-end (separating), closed-end (non-separating), and continuous chain. They share the same basic interlocking mechanism but differ in how the ends are finished — and those differences determine which garment or product each is suited for, how each is installed, and what the sewing process looks like.
Open-End Zippers: Full Separation via Pin and Box
An open-end zipper allows both tapes to detach completely. This is made possible by two dedicated components fixed to the base of the chain:
The pin — a rigid element attached to the bottom of one tape. The box — a reinforced receptacle attached to the bottom of the other tape. To engage the zipper, the pin is inserted fully into the box and the slider is drawn upward, locking the two tapes together as it travels. When the slider returns to the base, the pin releases from the box and the tapes separate.
Applications for Open-End Zippers
The full-separation feature is essential wherever the garment needs to open completely: jacket fronts, cardigan fronts, sleeping bag entry points, wetsuits. It is also the standard construction for two-way separating zippers — which add a second slider, allowing the zip to open from the bottom as well as the top, giving ventilation control on long outerwear or cycling jerseys.
Sewing Open-End Zippers
Open-end zippers require attention at the base. The pin and box assembly adds bulk compared to a standard tape end, and the seam at the base must be finished without obscuring or binding the box opening. Standard practice is to leave the pin-side tape end accessible below the seam, with the box opening clear of any stitch line. If the box is sewn over, the zipper cannot be engaged.
Closed-End Zippers: Fixed Base, Partial Opening
A closed-end zipper does not separate. A bottom stop — a small element crimped or moulded across both tapes at the base — holds the two sides permanently together and prevents the slider from leaving the chain. The opening is accessible only as far as the slider travels, not fully detachable.
Applications for Closed-End Zippers
Any closure that does not need to open completely: pockets, trouser flies, bags, purses, cushion covers, pillow cases, upholstery, luggage compartments. Closed-end zippers are also simpler to handle in production than open-end — there is no pin/box alignment step, and the bottom stop eliminates one failure mode.
Double-Stop Variants
Closed-end zippers are available with two-stop variants for specific design purposes:
O-shaped double bottom stop — two bottom stops with a loop of chain between them at the base. The measurement is taken between the two stops. Used for garment designs where the lower section of the zip is intended to be decorative rather than functional.
X-shaped double top stop — two sliders travelling toward each other from opposite ends, each with its own top stop. The chain is measured between the two slider positions at maximum travel. Used for two-way pocket designs and specific fashion applications.
Sewing Closed-End Zippers
Because the base is fixed, closed-end zippers are dimensionally stable during installation. The main sewing consideration is ensuring the bottom stop sits at the correct position relative to the seam — if the stop falls at the seam line rather than below it, the slider will reach the stop before the closure is fully made.
Zipper Chain: Cut-to-Length, No Stops
Zipper chain — also called continuous zipper or zipper by the metre — is exactly what the name says: an uncut length of zipper tape with teeth on both sides but no stops at either end, no pin, and no box.
Why Chain Exists
Chain is the format for applications where standard cut lengths don't match the requirement, or where the manufacturer needs to control every dimension of the finished zipper themselves. Furniture upholstery, for example, often requires zipper lengths that match a specific cushion dimension — not a standard 30, 40, or 50cm step. Tent manufacturers use specific lengths that change by model. Technical textiles and industrial applications routinely need non-standard configurations.
Working With Chain
Chain is ordered by the metre and supplied on a roll. The manufacturer cuts to the required length, then adds top stops, bottom stops, and sliders using dedicated application tools or hand-crimping equipment. The cost per zipper is lower than pre-finished options when large volumes of a specific length are needed — you pay for teeth and tape, not for individual stops and sliders.
Sewing Chain
Chain without stops must be handled carefully during installation because the slider can run off either end during handling. Standard practice is to install the slider and apply stops before or immediately after cutting, rather than leaving cut chain unfinished. Apply the bottom stop first on closed-end applications; the pin/box on open-end — then install the slider from the top before applying the top stop.
Which Type for Which Application
If the product opens completely (jacket, coat, sleeping bag, wetsuit): open-end separating zipper.
If the closure is a pocket, fly, bag opening, or cushion seam: closed-end zipper.
If the required length is non-standard or you're producing large volumes of a single length: zipper chain cut to specification.
For more on the wholesale ordering process including chain supply by the metre, see our wholesale zipper purchasing guide. For a full breakdown of tooth materials (nylon coil, plastic, metal) and how construction type interacts with material choice, the zipper types comparison guide covers the material differences in detail.
Our range covers open-end, closed-end, and chain formats in nylon coil, moulded plastic, and metal teeth. If you're working out which construction suits a specific garment, our team can run through the options with you.
