Ketofa 4 Pcs Presta Bicycle MTB Valve Caps French High Pressure Anodized Dust Cover 4 Colors Valve Type : Presta Material:Aluminium alloy Valve cap with sealing ring,more durable than the original one. Prevent dirt and water get into the inside of valves and potentially jamming or contaminating the selling surfaces and causing a leak. These are for the valve with the twiddly bit you unscrew to inflate the tyre, they will not fit car type valves.