The kryptonite evolution series 4 disc lock with case hardened 12 inch kryptonium steel shackle for maximum security the 14mm hardened max performance steel shackle resists cutting and leverage attacks double deadbolt locking mechanism for extensive holding power high security disc style cylinder with more then a million key variations reinforced anti drill anti pull cylinder protection system sliding dustcover protects and extends cylinder life 3 keys one lighted with high intensity b