The Iconic SILCA Presta Only Head (formerly the 30.0) has been updated during its transition to American production. The classic brass material has been replaced by aluminium, while the design has been re-imagined as an heirloom-quality objet d’art.The utmost care has been taken to machine the part using mono-crystalline diamond tooling to get the perfect surface finish, while the final feel benefits from an investigation into more than 20 different styles and depths of knurl so that it will feel \'just-so\' in your hands as it provides a lifetime of useful enjoyment. This is truly a tool you will hand down to your children and they to theirs. 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!Key FeaturesIconic Silca Presta Head Design - in use by more pro team and shop mechanics than any other!,Aluminium,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.