Feature:1. Battery Reminder: When the battery quantity drops below 20%, the red light of the lock will flash and the mobile APP will also display a low battery prompt; When the battery quantity is below 10%, it will not be able to lock (normal use for about 8 months)2. APP Control: Select automatic unlocking, no need to operate the phone. When the phone approaches, the blue light on the lock flashes to indicate unlocking status; When the phone leaves, it is in a locked state; Locking and unlocking by turning on and off BT3. Alarm Release and Password Change: When the alarm is triggered, if the phone is close to the lock and connected, the alarm can be released (the phone BT and APP must be open); Six digit password setting, supports password modification4. Multiple Functions: Can pair multiple mobile applications, easy to operate, as long as your phone is close to the BT chain lock to unlock; Equipped with vibration alarm function; Low power consumption, with low battery warning function5. Water Proof and Practical: This chain lock has an IP44 water proof rating, making it suitable for any occasion; The alert sound is above 110 decibels, suitable for bikes, electric vehicles, motorcycles, and moreSpecification:Item Type: BT Chain LockMaterial: Manganese Steel Chain, ABSBattery Type: 3 x AAA Battery (not included)Chain Diameter: Approx. 6mm / 0.24inChain Length: Approx. 80cm / 31.5inFunction: Anti Cutting Function: Alert when the steel rope is cutAnti Dismantling Function: Alert when the screw is dismantledVibration Function: Alert for 30 seconds when the lock body vibrates or movesWater Proof Function: IP44 Water ProofAlert Sound: 110dB and above.Package List:1 x Chain Lock1 x Screwdriver1 x User Manual