Air compressor unloader pilot valve, made in the United States. The valve is used to operate a compressed air system at a constant run with a preset pressure operating range to actuate throttle controls, intake unloaders or air-actuated discharge valves. The valve preset operating range is 95-125 psi, it has 1/4" Female npt threads that would be used for air hook-up or screwed into the compressor tank and has 1/8" female npt threads on the side of the valve (as shown in the picture). The 1/8" threads are the port used to control a throttle, intake unloaders or discharge valve. If more than one outlet is needed it is common to use a "tee" to make multiple ports. This valve's preset pressure can be adjusted, below the manual unloader lever on the top of the valve there are two screw settings that can be adjusted. The bottom one, which is larger than the top one, controls the valve itself Do not adjust the bottom one, the top one, which is the smaller one, right below the manual lift lever, controls the pressure setting. When screwed in, it will increase both cut-in and cut-out pressure. When it is screwed out, it will decrease both cut-in and cut-out pressure, it is not recommended to be adjusted more than about 15 psi in either direction. Specifications: Operating Pressure: 95-125 psi Max Operating Temperature: 300° F Max Operating Pressure: 200 psi Air Inlet Threads: 1/4" Female npt (measures about 1/2" diameter) Air Outlet Threads: 1/8" Female npt (measures about 3/8" diameter)