Window Security Alarm,built-in sensor detects vibration and instantly alerts you of a potential break-in and scare away burglars with 125dB loud alarm. . Unique Roller Vibration Sensitivity Ajustment, will not go off in rain,wind, etc.Help to prevent false alarms. . Ultra-thin (0.35inch) design.Perfect for home, office, garage, RV, dorm room, warehouse, Jewelry Shop, safe. . Easy Installation: No wiring needed, simply peel and stick an alarm on anywhere you need. . Low Battery Warning: The window sensor alarm can be used for one year(stand by) without changing the battery frequently. When the battery ( 3 LR44 batteries included) voltage is too low, the alarm will DIDI alert. Remind that you need to replace the battery.Don't worry about not working.