Silca Pump Elastomer Seal 242 for Presta Chuck

Newly updated and improved the SILCA #242 gasket utilises a high tech, fully synthetic Elastomer base material rather than a black carbon-filled natural rubber of previous gaskets. With a life expectancy of more than 5 times the carbon-filled rubber or Buna-N materials used previously this unique, bright-red gasket boasts two-stage seal geometry which enforces closure on both valve stem and at the base of valve core threads resulting in improved durability and an air-tight seal in even the harshest of environments.
This replacement Silca Elastomer Seal for Presta Chucks slips onto the valve stem with a reassuring 'click', while unique internal geometry actually utilises line air-pressure to compress the gasket onto the valve stem: the higher you pump, the harder it grips the stem! Of course it won't come as any surprise to learn that more than 20 companies world-wide are making pump heads and gaskets copied from Silca's design, but none of them can come close to the precision and technology achieved with this genuine #242.