This listing is for one new 95-125 PSI piloted discharge check valve / unloader valve combo with a 1/2" female npt for the air inlet port. This check valve combo is made by Conrader in the U.S.A., It is an NS series valve. This valve is usually used on compressors that pump less than 20 CFM, and can be used on gas or electric compressors. This valve is equipped with a in line check valve and attached to the side is a built in piloted unloader valve set 95-125 PSI. This valve also has a muffler in the exhaust air port to quite down the unloaded exhaust air that is released once the compressor reaches 125 PSI. On the side of the valve it has an 1/8" female NPT port, to control the throttle on a gas engine and/or unloader valves on some pumps.