This replacement valve is an authentic manufacturer-supplied item that is specially designed for Rolair air compressor pumps. Reed valves are commonly used in high-performance versions of the two-stroke engine, where they control the fuel-air mixture admitted to the cylinder. As the piston rises in the cylinder a vacuum is created in the ...Read morecrankcase beneath the piston. It is an identical replacement for a damaged or a missing component that was installed on a new unit. Refer to the owner's manual and the appropriate diagrams for your model to ensure the correct repair procedure. A wrench set will be needed to remove the old and secure the new. Note, this high-quality valve is made of durable metal and is sold individually.