The Master Lock No. 6121KA ProSeries® Weather Tough® Covered Laminated Padlock, Keyed Alike – multiple locks open with the same key – features a 2-1/8in (54mm) wide heavy steel body to withstand physical attack and a 1-1/8in (29mm) tall, 5/16in (8mm) diameter hardened boron alloy shackle for superior cut resistance. The exclusive cover protects this padlock from harsh elements & a high security, rekeyable 5-pin cylinder with spool pins is virtually impossible to pick.