Product Details: The OTR R-12 Style Vertical 4-Port Relay Valve ensures Expertise Built In™, with the right amount of application or release your rear air brake requires in a fast, safe manner. This OTR relay valve is compact yet powerful and eliminates brake lag. This 4-port relay valve weighs approximately 2.3 lbs. It also has a cracking pressure of 4.0 psi. In addition, this OTR relay valve's innovative design and composition ensure consistent and reliable braking at safe distances. In the end, this heavy duty service relay valve is strong, efficient, and long-lasting choice for your truck and trailer. FleetPride is your First Click in Heavy Duty®.