A pressure switch monitors the pressure in your tank and turns the compressor on when it's time to fill the tank back up. These 30-Amp, weather-proof, 1/4" NPT-threaded pressure switches will keep the air pressure between 165 and 200 PSI and are made by EZ Air Ride. We decided to go above and beyond to provide our customers with a pre-wired, weather-proof switch because we found that some customers (like C10 owners) mount their tanks under the bed where the components are exposed to the elements. Not to mention we have heard of condensation building up in a trunk. The switch gets rid of all issues related to these worst-case scenarios. Simply mount the switch on your tank and connect one wire to a keyed power source and the other to a ground.