The Oxford Products Magnum U-Lock is ultra-strong with a high security, independently approved 16mm shackle lock with a hardened steel construction and has undergone rigorous testing, achieving Sold Secure GOLD, ART 4*, SBSC and FG certification. The Magnum has a critical replacement service. When you buy your Magnum, note the number on a metal tag attached to the keys. Please keep this in a safe place; then, if you are unfortunate enough to lose all your keys, it will be possible to get a new key made up for you. It has an ultra-strong double locking mechanism with a high-tech pick-resistant locking system, and it is saw, bolt cropper and drill-resistant. It has two keys, a lock head dust cover and a carry bracket for cycle use. It is also 5 minute attack test.