The Master Lock heavy duty outdoor padlock with key features a 1-3/4 in. (44 mm.) wide laminated steel body for maximum strength and reliability, and is surrounded by stainless steel and zinc outer components for weather resistance. Octagonal lock shackle is 5/16 in. (8 mm.) wide in diameter and is 2-1/2 in. (64 mm.) long and made of tough-cut boron-carbide, 50% harder than hardened steel, offering maximum resistance from cutting and sawing.