Outfit your semi truck to be Ready for the Road Ahead with enhanced pneumatic system safety, with the Haldex 1/8''-27 NPT Male Electric Low Air Switch. With a specialized design, this replacement switch is able to monitor the pressure of a system to engage / disengage the compressor to keep the air pressure at a stable level. Manufactured with an easy-to-install and straightforward design. FleetPride is your First Click in Heavy Duty .