Setting the standard for disc wheel head adaptors since Francesco Moser's hour record in 1984, the Silca Press on Disc Wheel Pump Adaptor has an ultra-durable lightweight 6066-T6 aluminium construction and a CompressionHead design that allow you to tighten the gasket by over 200% by simply rotating the cap 180clockwise on your bike pump.The Silca Press on Disc Wheel Pump Adaptor fits only Presta valves and thanks to the CompressionHead technology it will fit even the most worn valves. The gasket is constructed from Silca's high-tech 252 Elastomeric rubber, which borrows technology form industries that require an air-tight fit. This means the gasket has a lifespan five-time longer than that of carbon filled rubber or Buna-N rubber gaskets used by rival pumps.With its slimline aluminium design, the Silca Press on Disc Wheel Pump Adaptor fits neatly into any disc wheel and can handle pressures up to 393 psi. The full metal construction means there are no plastic parts to fail and the Sc