Designed for use with round rail on wood-frame, metal-clad doors using a 2 x 6 in top lateral. 1/2 in offset 9 in bolt (with 7 in thread) adjusts door vertically and laterally (1 in) from inside building. Flexible trunnion design resists door damage. Precision-ground and hardened steel roller bearings, axles and sleeves provide longer life and easier operation. Interchangeable with other brands of round rail. Safe working load - 300 lb per hanger.