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 pressure switches will keep the air pressure between 110 and 150 PSI.

Where to install:  This simply mounts on your tank, with one electrical connection going from the positive terminal of your battery, and the other going to the red wire on your compressor.  When running multiple compressors, it is recommended that a heavy duty solenoid be used to protect your compressors and pressure switch from overloading!