The Solenoid Valve for the Digital Control Gauge controls the air flow from the compressor going to the tire. The solenoid valve connects to the pressure sensor on the electronic board allowing the air machine to determine the amount of pressure in the tire. Included with the solenoid valve is a protective sleeve as well as two micro-filters. Compatible with SC05-SS, SC09-SS, SC12-SS, WM-SS, PNT PRO & PNT 4.