Air compressor unloader pilot valve, made in the USA. 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 valves preset operating range is 125-150 PSI, it has 1/4" male 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 which can be purchase at a local hardware store. 

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. 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 and when 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:

• Max Operating Temperature: 300° F
• Max operating pressure: 200 PSI
• Air Inlet Threads: 1/4" Male NPT (measure about 1/2" diameter)
• Air Outlet Threads: 1/8" Female NPT (measure about 3/8" diameter)
• Also equipped with a manual unloader/control lever which is located at the top of the valve.
• If lifted in the straight-up position it opens the valve and puts pressure to the throttle control, head unloaders or discharge valve. 
• This valve is precision machined, all brass construction with stainless steel mesh filter on the intake side of valve for a dirt-free operation.