The Master Lock No. 6001NKALT Government Laminated Steel Padlock features a 1-3/4in (44mm) wide laminated steel body and a 3in (67mm) tall, 5/16in diameter hardened steel shackle for excellent cut resistance. Designed to stringent government standards, the 5-pin tumbler cylinder with BumpStop® offers more than 10,000 key changes and a dual locking mechanism provides superior pry resistance. For added security, padlock comes with non-removable keys to ensure padlock is never left unlocked. BumpStop® Advanced Cylinder Technology protects against lock bumping.