About this item C Series padlocks are designed to provide patented high security control and strong physical protection for padlock security. All C-Series padlocks are manufactured with a hardened steel shell and a hardened steel shackle. They are available with or without a shackle guard for added protection, and are also available with a pop open or fully removable shackle. Varying in different diameters and clearances, the C Series line accommodates all padlock requirements. Application High security padlock, for general use with Mul-T-Lock hasps or shackle protectors. Operation Unlocking with 55?-65? key rotation. Materials Shell: Hardened Steel. Core: Black Plated Solid Brass. Shackle: Hardened Boron Alloy Steel. Mul-T-Lock's MTL600 mechanical platform addresses High Security concerns while responding to functional needs. Building on four decades of extensive experience and MTL600 key platform's proven technology and global success, MTL600 utilizes patent technology for enhanced High Security. Available in all formats and product types, MTL600 key platform provides advanced High Security and protection with a single key that can fit into all products for real convenience. Using advanced technology, MTL600 combines an enhanced variation of the telescopic pin mechanism with a special patented floating element to meet the highest security standards.