Product Details: The OTR Trailer Spring Brake Priority Valve ensures Expertise Built In™, being designed with high quality and precision. This OTR spring brake priority valve meets FMVSS-121 requirements and can be used on trailers to control parking and emergency brake function. The OTR spring brake valve ensures immediate and adequate air supply to release the spring brakes. Once the brakes are released, the reservoir begins filling, allowing driving without the need to wait for the compressor to refill. As a result, this heavy duty priority valve supplies reliable and superior brake system function. FleetPride is your First Click in Heavy Duty®.