Technical Support FLEXSEAL®


How to measure the length

(One end closed)
(Both end closed)

The method of specifying the length of FLEXSEAL® zipper differs by brands.
New Zipper(BDM) uses OL and YKK/Dynat uses EL.

OL = Over all length (includes top stop and bottom stop)
EL = Elements length (without top stop and bottom stop)

Maximum / Minimum Order Length

Size Tape Minimum length Maximum length
85SEY CR25 (Chloroprene) 15cm -
P23 (Polyurethane) 20cm -

Smart use of zippers

  • Close the zipper till the slider completely touches the stop to ensure tightness.
  • Overstretching of the top and bottom stops should be avoided.
  • FLEXSEAL® is sensitive to over bending.
  • If the slider should jam during closure, DO NOT FORCE IT. Pull back the slider, remove the obstruction and slowly attempt to close it again. Excessive force may destroy the fastener.


  • After use, the zipper should be rinsed in clean water. Any object (sand, mud, etc.) found in or outside of the elements before operating the zipper may result in poor tightness or may damage the zipper.
  • Do not dry clean, machine wash nor iron.


  • Regular cleaning and silicone greasing is advised in order to prevent damage to seals. 

Installation Guide

Tape material Possible installing method
CR(Chloroprene) Sewing & seam seal, Gluing
PU(Polyurethane) Sewing & seam seal, Welding

In case of inserting SEY to the fabric by stitching, seam taping on both the front and back sides is highly recommended.

This does not apply when using glue or welding.
Either Neoprene or PU is extruded to the base chain to create a fin and a coating to offer protection from the outside.
However, while offering fully coated protection on the front side, the base fabric is exposed on the back side.
Having such construction, when inserting SEY to the end product via stitching, water or other types of liquid may soak into the base fabric via exposed sewing thread.
Consequently, such water/liquid may migrate through the base fabric further down to the exposed area and may result in leaks.
To prevent water migration, we highly recommend covering the sewing thread by seam taping on both the front and back sides of the product.


  • Store with the zipper completely opened, taking care not to bend it. The storage in a closed position for long period will cause malformation of the sealing areas. Also, storing partially opened will cause zipper bending. As these occur, slight leaks are possible.