Silca 242 Pump Chuck Seal

The new 242 gasket utilizes a high tech and very red, fully synthetic elastomer base material rather than a carbon black filled natural rubber of previous gaskets.
This unique bright red gasket borrows from industries which require air-tight seals in the harshest of environments, and tests to a life expectancy of more than 5X the carbon filled rubber or Buna-N materials used previously.
New Two-Stage seal geometry seals on both valve stem and at the base of valve core threads resulting in a more positive seal and improved durability.
The new gasket slips onto the valve stem with a positive and satisfying 'click', while unique internal geometry actually utilizes line air pressure to compress the gasket onto the valve stem: the higher you pump, the harder it grips the stem. Iconic Silca Presta Head Design - in use by more pro team and shop mechanics than any other. 17-4 Stainless Material, 6X the strength and 2X the hardness of Brass. Full Synthetic Elastomer 242 Gasket. 5X the durability of traditional rubber materials. New Two-Stage gasket sealing geometry optimized for all Presta valve stems. Pressure amplifying dome geometry uses air pressure to clamp valve stem. Schrader valve thread on hose side threads into any Schrader compatible hose attachment. Hand-Crafted with pride in Indianapolis, USA.
Specifications
Synthetic elastomer base material
5X the durability of traditional rubber
Two-Stage sealing geometry optimized for all Presta valve stems
Pressure amplifying dome geometry uses air pressure to clamp valve stem
Fits all bell-shaped SILCA Presta heads
9mm H x 21mm OD