The big boss ultra strong alarm lock is the strongest most secure lock oxford have ever manufactured featuring a thick 16mm shackle the big boss lock can be used as a disc lock or can be combined with the supplied 12m long 12mm thick 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 big boss is also water vibration frost and heat proof so