Equip your semi to be Ready for the Road Ahead , with the Transglobal 6" Steel Roll Up Door Center Hinge, a key component to provide your semi with a smooth and reliable spring-operated door assembly. To provide your roll up doors with a seamless means of opening and closing, this replacement hinge is crafted with precision-manufacturing and friction-free components. Engineered with corrosion and rust-resistant metals for enhanced durability in humid climates and rough conditions. FleetPride is your First Click in Heavy Duty .