Power Hinge - All SteelEngineered to last longer, install easier, and provide greater safety than conventional gate hinges. They are designed for industrial, high traffic applications with heavy wrought iron or aluminum gates. double 5 8 in. ball bearings for smooth operation 3 4 in. solid stainless steel shaft, grounded and tempered to Rockwell standards Continuous cycle operation, self lubricating no grease fittings Offers a unique design so the gate never hits the post