Condor MDR3 heavy duty pressure switch used many compressors including Eagle and Maxair model C5160V1 air compressors. 4 port 1/4″ NPT  connection manifold, with 90 degree 1/4″ push to connect unloader valve. Top cover mounted off-auto selector. Factory set 115 psi on, 135 psi off. Switch has 3 pairs of contacts. use all 3 for 3 phase power or any 2 for single phase units. Maximum amperage 25 amps @ 220volts.

Tech Tip: If the switch unloader valve is continuously leaking air, the problem is probably a defective in-tank check valve, and not the pressure switch.