Our toughest Lock Alarm to date! Its extremely high resistance to cutting (from both mechanical and power tools) has earned the Lock Alarm Ultra the Sold Secure (UK’s Master Locksmith Association) Bronze rating. This high strength, easy to use, U-lock with alarm is ideal for when you need to secure your property in vulnerable locations. When an attempt is made to cut through the shackle a 110 decibel siren starts sounding. In addition there is a shock sensor that will detect if the lock casing is being attacked and sound the alarm accordingly.