The boss ultra strong alarm disc lock is the strongest most secure lock oxford have ever manufactured featuring a thick 14mm shackle the boss disc lock can be used as a disc lock or can be combined with a chain and used as a padlock featuring an audible alarm that produces 100db of sound that can be heard 500 metres away when the lock is tampered with the big boss is the ultimate thief deterrent the boss is also water vibration frost and heat proof so it can fend off the elements tooth