Precision cylinder protection, thousands of key changes, tough, laminated, cadmium rustproof steel case; nickel-plated shackle. Removable key- change number for added security. Pair of brass keys included with every lock. Case-hardened steel shackle. Exclusive dual steel locking levers independently lock each shackle leg for increased protection. Patented taper assures smooth vertical shackle movement and precise engagement of locking levers. Proprietary rustproofing for longer life. 1-3/4" wide case, 5/16" diameter shackle, and 3/4" wide horizontal shackle clearance.