The Master Lock No. 6271 ProSeries® Hidden Shackle Padlock features a 2-7/8in (73mm) wide reinforced die cast body that withstands forcible attacks and a 3/8in (9mm) diameter boron alloy shackle. The Lock body conceals the shackle, defeating attempts to pry and cut. Ideal for transportation, vending & industrial applications, the high security, rekeyable 6-pin cylinder with spool pins is virtually impossible to pick.