Product Details: Prepare your vehicle to be Ready for the Road Ahead™ with the Haldex 1/2" Reservoir NPT FF2 Full Function Trailer Valve, a replacement product designed for a wide range of pneumatic applications. This single valve system is designed to regulate the air supply built up in your vehicle's components. Manufactured with built-in pressure protection and anti-compounding functions. FleetPride is your First Click in Heavy Duty®.