The oxford alarm d u lock max is the largest alarm lock that oxford produce and it has the capability of detering the sneakiest of thieves and can cope with large or oddly shaped frames with a sold secure silver rating the lock is ideal for busy towns and cities on a mid to high end bicycle featuring a highly unnatural 120db alarm as loud as a fire engines sirens or a chain saw the lock draws everyones attention to your bike and the person fiddiling with your lock you have the option to ac