The Bendix PP-DC® Park Control Double Check Push / Pull Valve is the perfect solution for controlling air pressure in your system. This valve automatically moves from the applied position to the exhaust position when the total system pressure drops below 20 to 30 psi, ensuring that your system always runs at optimal pressure. It receives air supply from the primary or the secondary service reservoir, whichever is at the higher pressure. The valve is made of noncorrosive non-metallic material to ensure it lasts longer. FleetPride is your First Click in Heavy Duty®.