Update your semi truck with precise control of the pneumatic cylinders, with the OTR 3/8" NPT 4-Way Air Pilot Spring Return Valve with Expertise Built In. To ensure the safe operation of compressed air throughout a vehicle, this replacement valve works to regulate the flow by using spring mechanism to return the valve to its default position. Built with four ports to offer complete control over the flow of compressed air. FleetPride is your First Click in Heavy Duty.