Ensuring Expertise Built In , the OTR Multi-Function Trailer Valve has a precise and innovative design, ensuring optimal function, consistency, and long life. This OTR multi-function trailer valve manages the parking and emergency brakes. It also utilizes the emergency brakes if the trailer supply line loses pressure. This OTR multi-function trailer valve is high-quality and reliable as it meets FMVSS-121 requirements. As a result, this heavy duty multi-function trailer valve optimally handles the demands of the road. FleetPride is your First Click in Heavy Duty .