The ADAPTRAC hubs (patent pending) are the components that allow the transfer of C02 to and from the control valve and the rotating tire. These are fitted internally with special, extremely low friction rotary seals. Secondary seals at the outboard adaptors create a seal around the removable axle upon tightening of the axle lever. A 1/4″ one-touch output/input fitting comes threaded into the hub body to connect tubing to the valve stem of the tire. Seals are replaceable with an ADAPTRAC seal replacement kit and specific ADAPTRAC tools.