Keyed Alike - The lock weighs 1.68 lbs. ProSeries Padlocks are designed for Commercial/Industrial applications Search 6230NKA for the 2, 3 & 4-pack listings. Longer shackle available, search 6230NKALH. 7/16 thick shackle and 1-1/8 (29 mm) inside height clearance. Dual ball bearing locking mechanism resists pulling and prying High security, rekeyable 5-pin cylinder with spool pins is virtually impossible to pick Master Lock High Security Padlocks One Keyed Alike Padlocks - Model # 6230NKA LIFETIME GUARANTEE! Lock bumping a surprisingly simple method of breaking in through locked doors and padlocks - is undoubtedly the newest emerging threat to personal property security. And virtually all locks in use today are particularly vulnerable to bumping. Until now. BumpStop Advanced Cylinder Technology employs an innovative, patent pending design which utilizes a unique reverse rake tapered driver pin, high performance springs and tightly machined cylinder chambers. During a bump attempt, this design prevents the transfer of force from the bump key to the pins and therefore blocks rotation of the cylinder so that the lock remains locked.