Suits disc rotor locking. Security Rating 80 Yellow colored shackle to further remind rider that disc is locked. Large 55mm x 55mm opening fits many disc and rotor openings. Massive 16.8mm hardened steel shackle resists all attack from cutting, prying or jacking. X4P Quattro Bolt locking system secures the shackle on four sides for ultimage protection. Included disc reminder helps prevent riding off while rotor is still locked.