This locking clip-on 90° valve stem extension makes it easy to add air to your tire when you have limited clearance between the end of the valve stem, and the hub or brake rotors. To operate, press silver lever then press the extension firmly onto the tire valve stem. Release the lever and the extension locks onto the tire valve stem. To add air, connect a CyclePump or an air hose to the input stem of the extension and fill the tire. To remove the extension press the silver lever. Air inside the tire will pop the extension off the stem, with no loss of tire pressure. Remove the valve stem extension before operating the vehicle. Minimum clearance needed to fit this 90-degree extension is 1.8" from end of the tire valve stem to the wheel hub.