The Master Lock Pro Series Padlocks give you extremely high security against physical attacks. They are very rugged & will work in extreme weather conditions. The Pro Series offer you a real difference in security, dependability & convenience. 2-3/8 (61mm) wide laminated steel body for superior strength Hardened boron alloy shackle for superior cut resistance High security solid iron shackle shroud resists harsh physical attacks 5-spool pin tumbler cylinder for added pick resistance Removable cylinder can be replaced or repinned Dual ball bearing locking mechanism resists pulling & prying Supplied with 2 keys Keyed to Differ