The Silca 242 Gasket for Presta Chucks utilises 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 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!
This design is so iconic they've found more than 20 companies world-wide making pump heads and gaskets copied from this, but none of them can come close to the precision and technology in the new 242.
Fully Synthetic Elastomer Base Material
5X the durability of traditional rubber materials
New Two-Stage sealing geometry optimized for all Presta valve stems
Pressure amplifying dome geometry uses air pressure to clamp valve stem
Fits all prior SILCA Presta heads
Made in USA