The Iconic SILCA Presta Only Head (formerly the 30.0) has been updated during it\'s transition to American production. The classic brass material has been replaced by the much more exotic Silca 17-4 Stainless Presta Head, a precipitation hardening stainless utilized in aerospace, petrochemical processing, military aircraft, and even as ultra-high strength bicycle tubing. Whereas brass may have been a material to last a lifetime, 17-4 is a material to last many lifetimes. 17-4 is more than 6X stronger than brass and 4X harder resulting in parts that last longer and are nearly impossible to damage or wear out. In a world where aluminium is used to replace brass for cost, and plastic is used to replace aluminium for cost, and so on, we felt the need to re-imagine this most iconic of cycling tools 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 of the part 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 them in turn onto 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!Silca 17-4 Stainless Presta Head FeaturesIconic 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 BrassFull Synthetic Elastomer 242 Gasket5X the durability of traditional rubber materialsNew Two-Stage gasket sealing geometry optimized for all Presta valve stemsPressure amplifying dome geometry uses air pressure to clamp valve stemSchrader valve thread on hose side threads into any Schrader compatible hose attachmentHand-Crafted with pride in Indianapolis, USA