Master Lock used the toughest boron alloy material & cutting edge technology, registering over 40 patents, to create Excell: a truly high security padlock that is 50% stronger than a standard padlock. These padlocks have a weather resistant cover, to protect the lock even in extremely bad weather conditions. Ideal for securing factory fences, sheds or store front gates. 48mm laminated steel core Weather resistant cover for added protection against extreme conditions Exclusive octagonal boron-carbide shackle for maximum cut resistance Double deadbolt locking for added protection from prying & hammering 4-pin cylinder