The Strongest U-shaped Lock (Alarm Lock/ALARM LOCK BLM-320) Introducing the strongest lock for crime prevention of bicycles and small bikes. Warning alarm sounds when it detects impact or vibration. ◆Shock Sensing Alarm Alert Warning alarm sounds when it detects impact or vibration. The 100 decibels loud alarm can be used to prevent crime. Completely waterproof, so it can be dropped in rain or water. Strong 1,200 kgf (1,200 kgf), so it is hard to break and locks firmly in a 0.7 inch (17 mm) thickness. Features a special shape key that is difficult to duplicate There are 3 spare keys. Battery type: LR44 (6 beads); Battery life: 6 months (when used in warning condition); Sound pressure: 100 dB; Size (H x W x D): 13.2 x 4.8 x 1.4 inches (338 x 123 x 35 mm); Weight: 3.3 lbs (1,050 g); Strength: 200 kgf; Accessories: Spare keys (1 lbs (1,2 kg)