The Master Lock No. 6840 ProSeries® Solid Body Padlock features a 1-3/4in (44mm) wide solid brass body to provide extra resistance in caustic, corrosive environments and a 1-3/16in (30mm) tall, 5/16in (8mm) diameter hardened boron alloy shackle for superior cut resistance. Designed for commercial/industrial applications, a dual ball locking mechanism resists pulling and prying and a high security, rekeyable 5-pin cylinder with spool pins is virtually impossible to pick.