Mammoth 11 mm Motorcycle Shackle Lock The Mammoth 11 mm motorcycle shackle lock is an 11 mm hardened steel motorcycle shackle lock with a double ball bearing mechanism in a toughened casing. A great deterrent which stops thieves in their tracks. Ideal both for independent use and when used in conjunction with a chain to complete your security setup. Motorcycle Shackle Lock Features: Toughened casing. 11 mm hardened steel shackle lock. Double ball bearing mechanism. Hinged weatherproof barrel cover. 62 mm (W) x 77 mm (H).