VIAIR Medium Duty Onboard Air System Intended for inflation of tires up to 33 inch. Designed to be installed and mounted onto the vehicle. Includes all parts needed for installation of you very own onboard air solution for tire maintenance and small pneumatic tools, except for air hose. Comes with one VIAIR 325C air compressor anda 110 to 145PSI pressure switch. 150 PSI maximum working pressure and 33% duty cycle Can be used to inflate helper bags for load leveling, inflate four tires up to 31 inches in diameter or use with heavy duty air horns. One year manufacturer's defect warranty included with copy of the receipt. Please check the manufacturer's website for a wiring diagram.