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 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