The Oxford HD Chain Lock is a fantastic mid-range lock which is light enough to be easily carried with you but still sufficiently secure to deter would-be thieves. --Hardened 9.5mm square link chain --Double locking padlock with hardened steel shackle --Key dust cover --Three Keys --Key Replacement Service --Sold Secure Bicycle Gold and Motor Scooters Silver approved The Oxford HD Chain Lock has a hardened 9.5mm square link chain and a tough, double locking padlock with hardened Steel shackle which can double as a disc lock. The Chain Lock has been Sold Secure Bicycle Gold, Motor Scooters Silver approved. The HD Chain Lock comes with three keys and key replacement service. On receipt of your chain lock, note your key number and keep in a safe place. In the unfortunate event that you lose all your keys, a new spare can be made up for you.