The oxford alarm d u lock midi is a thieves worst nightmare with a silver sold secure rating the lock provides the one of the highest standard of security for your bike the shackle of the lock is constructed with 14mm hardened steel and is accompanied by an unnaturally loud a 120db alarm which is activated when the lock is disturbed you have the option to activate the alarm when you are locking your bike simply turn the key once and youll hear one beep which means the alarm is activated t