Product code DUR 4
Material brass
Robust waterproof ring spring system

Product code DUR 4
Material brass

Robust waterproof ring spring system

Push-button fastening system on a ring spring basis specially developed for waterproof applications and waterproof laminates. Ideal for applications where waterproofness is required in addition to a high opening force and opening security (with side pull).

WetStop® is a proven fastening solution for rainwear and functional textiles for work, outdoor, ski, motorcycle and water sports and government clothing and equipment. The waterproof property also offers decisive advantages for many technical applications such as sports equipment, baby carriages, automotive, two-wheeler accessories and camping.

A Cap with sealing element
B Socket
C Stud
D Cap as Post with sealing element


  • Robust optics with WetStop® property
  • High locking force
  • Waterproof
  • High opening forces


  • Suitable for many laminates and membranes – We are happy to test your material
  • Semi-automatic application (see product catalog)
  • Special stamp required for waterproof processing


  • Waterproof clothing for public authorities, work and sport
  • Sports equipment
  • Technical applications

Function and advantages

The clasp is created by connecting the Socket and Stud, whereby the ring-shaped wire of the Socket expands when the Stud penetrates and encloses it when it snaps into place.

The waterproof cap and Socket as well as the Stud and waterproof Post are each riveted centrally. The proven WetStop® technology with integrated sealing elements reliably prevents the ingress of water via the cap and Post, i.e. neither from the outside nor from the inside.

The moving brass ring can be disturbing due to its movement noise. This applies, for example, to areas such as public authorities, hunting and golf. As an alternative, we recommend the silent FlexFix® product code DUP 40 Snap System in combination with waterproof Snap Caps.

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The WetStop®-technology

The principle of sealing

Waterproof WetStop® Fastening System prevents the ingress of water on non-pre-punched waterproof laminate. The sealing elements of the rivet cap and the rivet shank seal them with the laminate, which is pulled into the rivet opening and pressed, during the installation process.

Waterproof Fastening System

Standard Fastening System

Waterproof WetStop® Fastening System

The use of the waterproof WetStop® Fastening Systems is particularly recommended for the production of truly waterproof garments. In order to prevent water from penetrating into the cavity and thus the risk of rotting of the material, it is essential to use waterproof closure components both on the top (outside) and bottom (inside).

YKK has developed a comprehensive system selection together with the users of technical textiles.

The waterproof WetStop® products from YKK exceed the specifications of all manufacturers and have proven themselves for decades. WetStop® can be used for a wide range of laminates and membranes. Also discover the durable FlexFix® WetStop® Snap Systems product code DUR 4, each available in brass or stainless steel.

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The quality test for watertightness

Test method

The watertightness is tested according to the internal YKK factory standard WN17.28, which even exceeds the specifications of DIN EN 343:2019-06. Provided the carrier material is suitable, we achieve a water tightness of 0.3 bar over a 3 min. holding time. A pressure of 0.3 bar corresponds to a water column of 3 meters in height.

Attachment method

Place the sample with the test specimens attached (water-repellent side down) on the cylinder filled with water and seal with the hand spindle. Apply a test pressure of 0.3 bar and hold for 3 min. constantly. The test specimens are watertight if no water escapes from the top.

Execution and assessment

The test device shown is used for the water tightness test.

Sample execution

  • Sample: laminate size = 130 x 130 mm
  • Attaching machine: WPG 5041
  • Test specimens: 4 push-button connections, arranged in a square

Further design options

There are various design options available for WetStop® DUR 4, the main one being the design of the Snap Caps. For more information on the various caps and finishing options, please refer to our separate brochures on caps and finishing or contact our sales force directly.





WetStop® product code DUR 4

D (mm)
DRO 4.005
10,5 mm
Height Opening force
DRO 4.006
10,5 mm
Metal caps
DK 901/4 ½/5.073 WP
12,7 mm
Waterproof only in combination with waterproof posts
DK 901/6 ½/5.073 WP
15,4 mm
Waterproof only in combination with waterproof posts
Plastic caps
DK 901/4 ½/5.76M WP
12,7 mm
Waterproof only in combination with waterproof posts
DK 901/6/5.76M WP
15,0 mm
DK 9100/6/5.76M WP
15,0 mm
with grained embossing
DRK 40
11,4 mm
Your contact person
Nelson Martins
Nelson Martins Manager Sales & Marketing / Head of Sales & Marketing T +49 202 749-486 M +49 151 18691395 F +49 202 7493-6486

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