This 170/200 PSI pressure switch designed for high-pressure onboard air systems. Ideal for air horns that require high air pressure. Preset to turn on the compressor when tank pressure is below 170psi, and turn off the compressor when the air tank pressure reached 200psi, with a tolerance of 10%.  For 12-volt power source. With 1/8" male pipe thread, and 1/4" push-on electric terminals.