The Master Lock ProSeries 6321 Shrouded Padlock features a 21/8- in. heavy steel body that withstands physical attacks and a 3/4-in.-tall, 5/16 in. diameter hardened boron-alloy shackle for superior cut resistance. Ideal for use on perimeter gates and fences, the iron shroud protects the shackle from bolt cutters, and a dual-ball locking mechanism resists pulling and prying. The high-security, rekeyable 5-pin cylinder with spool pins is virtually impossible to pick.