Precision engineered pin-tumbler cylinders afford thousands of possible key changes. Patented dual-lever action, independently locks both shackle legs. Protects against pulling, shimming and rapping. Case hardening and special alloy steels make shackles highly resistant to cutting and sawing. Corrosion-resistant chrome and nickel shackle protection. Choice of regular or extra-strength. Cadmium rustproof bodies. Hardened boron alloy shackle. 2 brass keys included with every lock. Proprietary rustproofing for longer life. 17D and 17KA have 2 in wide case, 7/16 in Dia shackle and 3/4 in horizontal shackle clearance. 15D and 15KA have 2-1/2 in wide case, 7/16 in Dia shackle and 1-3/16 in horizontal shackle clearance. 651.7171 key number is 19T462.