Product Details: Equip your semi to be Ready for the Road Ahead™ with the Chelsea 1/4" Pressure Protection Valve, a sophisticated device that provides safe air pressure levels. By utilizing a sophisticated design, this replacement component is able monitor the internal pressure of the air brake system, preventing over pressurization by releasing air pressure once it exceeds a certain level. Built with innovative technology to reduce the chance of leaks and mechanical failures. FleetPride is your First Click in Heavy Duty®.