1.When a bike is intended to be stolen,loudly alarm will be issued.                   
2.Safe and reliable 4 digital codes electronic lock.                                                              3.high sensitivity;3 level for sensitivity adjustment.                                                   4.Rechargeable lithium battery,>6 month using life(20 alarms/day),easy charge,never take out the battery.                                        
5.Reset key to avoid forget your code,easy use.                                                               6.Alarm sound:>120db.                                  
7.Power:3.6V rechargeable lithium battery*1pcs