New, old stock in original box. World American RT-4 Valve KN26000 World American is the heavy duty, export division of Midwest Truck Auto Parts, Inc. Supplying drivetrain, brake, steering and suspension, wheel attaching, rotating electric, clutch and hydraulic components to the heavy-duty aftermarkets. Get superior OEM quality replacement parts, backed by professionals with the experience and knowledge to help get heavy duty vehicles back on the road quickly. World American manufactures manual transmission components, differential components, complete rebuild kits, bearing kits, ring and pinion gear sets, cases, housings, axles, yokes, u-joints, air brake valves, brake chambers, brake hardware kits, air springs and more. World American, Where Quality Meets Value! RT4 Multi-Function Trailer Valves Meets all FMVSS-121 trailer requirements for spring brake control and other regulations. Used on trailers to control both parking and emergency brake functions. Applies emergency (parking) brakes upon loss of trailer supply (emergency) line pressure. Controls reservoir charging. Interchangeable with competitive units.