The oxford shackle duo u lock 320 with cable is a partnership that can bring the most experienced thieves to a halt the shackle has the three most important requirements on lock down the lock comfortably passes the gold sold secure rating by using a 14mm hardened steel shackel and body mated to a simple but powerful locking mechanism the lock is supplied with 3 keys and oxofrd also offer a key replacement service for if you have lost or damaged your original keys