Ultra cuffs are the first forged aluminum rigid frame restraint Lightweight round smooth edges interchangeable lock sets conical bows double sided keyways Added to these revolutionary design elements is a frame that is forged from 7075 T6 ordnance grade aluminum and permanently joined by 4140 heat treated spiral locking pins There is a keyway and double lock slot on each side of each restraint The lock assemblies are unitized and replaceable the frame geometry deep set teeth and precision smooth action eliminates the need for back loading