Sometimes , there's just not enough space around the tire's valve stem for the gas station air chuck and hose to reach. Brake rotors , sprockets and saddlebags get in the way and keep the air chuck from making an airtight seal. The Valve Stem Extension is the remedy to this problem. •Simply screw the extension in place on the stem , fill the tire to the proper pressure , remove the extension , and replace the valve stem cap • Helps get around brake rotors , sprockets , and saddlebags to get an airtight seal