Double Slider
A double slider is a zipper with two sliders on a single zipper, allowing it to open and close from either end or from any position in between.
Contents6 sections
Definition and Overview
A double slider is a zipper with two sliders on the same row of teeth or coil. By changing the position of the two sliders, the opening can be made from the top, bottom, or center, improving ease of use when worn or when stored.
“Two-way opening” is often used to refer to a double slider, but it may also be used to specify the opening style. In purchase orders and specifications, it is important to clearly state the slider orientation and whether a separating end is included.
Structure and How It Opens
A zipper consists of interlocking teeth, a zipper tape that holds the teeth, a slider that opens and closes it, and top and bottom stops that secure the ends. In a double slider, in addition to these parts, the orientation and stop positions of the two sliders determine the function.
With both sliders facing each other, called head-to-head, and with them facing opposite directions, called tail-to-tail, the opening position and appearance differ. In open-end styles where the bottom end separates, a separating end may be used, and it may be used as a two-way opening style that opens from the top and bottom.
- Head-to-head: a configuration in which the puller sides of the two sliders face each other.
- Tail-to-tail: a configuration in which the puller sides of the two sliders face opposite directions.
- Two-way opening: mainly for open-end zippers, a style that can be opened and closed from either the top or bottom side.
Types and Specification Checks
Double sliders come in different options depending on the type of teeth, such as metal, resin, or coil, the tooth size, the tape material and color, and the slider shape. The overall zipper specification is combined according to fabric thickness, required strength, and application.
Length is generally checked by the effective length from the top stop to the bottom stop of the closed zipper. However, because the standard may differ depending on whether a separating end is included and on the stop shape, confirm against the specification sheet, the actual sample, and the manufacturer’s dimensional notation.
- Tooth size and tooth type
- Zipper length and excess tape at the ends
- Open-end or closed-end type
- Slider orientation, puller shape, and presence of a locking mechanism
- Specifications for the top stop, bottom stop, and separating end
Main Applications
For front openings on outerwear and coats, they are used to create room at the hem when sitting and to secure range of motion while walking. In layered garments, the lower opening can also make it easier to adjust the temperature inside the garment.
For bags, cases, bedding covers, and interior goods, the center can be opened to access contents or to adjust the opening range. The longer the opening, the more important it is to consider the slider movement direction and operating position for the intended use.
Selection and Sewing Precautions
Because there are two sliders, before sewing, move the two sliders to the specified positions and check the opening direction. Keeping the left and right tapes from twisting and sewing them at a fixed distance from the tooth ends helps reduce tape waviness and slider catching.
When washing or product washing is performed, the sliders, or the teeth, may come into contact with other garments. Before use, check the closing position during washing, protection of the pullers, and discoloration or coating wear on metal parts, including the fabric and finishing process used.
In prototyping, check opening and closing to both ends, the movement when the two sliders approach each other, and waviness after sewing. In particular, for two-way opening styles, verify insertion into the separating end and the ease of operating the lower slider in conditions close to actual use.
Frequently Asked Questions
Are a double slider and a two-way zipper the same?
No, they do not mean the same thing. A double slider refers to a structure with two sliders, while a two-way zipper mainly refers to an open-end style that can be opened and closed from the top and bottom. Two-way products usually use two sliders, but not all double sliders are two-way.
Where do you measure the length of a double slider?
Generally, the effective length from the top stop to the bottom stop is checked with the zipper closed. However, the standard may differ for styles with a separating end, continuous chain, or special stop specifications. When ordering, confirm not only the required length but also the measurement standard and excess tape at the ends in the specification sheet.
Can a double slider be added later?
It is usually not easy to add only the slider later to a finished stop zipper. The end stops or separating end would need to be removed, which may damage the teeth or coil. Decide the required opening style at the planning stage and select a finished product with two sliders or a compatible chain.
