Also known as a "cold start" valve, this integral component releases air off of the piston and pump head after it shuts off, which allows the motor to start much more easily and efficiently. This also reduces overheating issues. 

California Air Tools Cylinder O-Ring gasket. Note: For newer models with motor serial# ending in "-O".

Rubber O-Ring Gasket for the cylinder head. Replace this gasket if you have to remove the cylinder head.

Electromagnetism Valve for 110V units.