Master Lock Commercial Magnum brings an extra measure of assurance for perimeter, equipment and vehicle security. To withstand the elements, Commercial Magnum(R) is made with a stainless steel cover and a chrome shackle. These durable padlocks extend use in any environment. The octagonal boron carbide shackle is 50% harder than the hardened steel used on typical padlocks - which increases resistance to cutting and sawing. The dual ball locking mechanism improves resistance to pry and impact attacks.