Features: Glass break alarm work by detecting the physical vibrations, with 125 dB loud alarm sound and red indicator blinks can help to deter/scare away the potential break-in and burglars effectively. Adjustable sensitivity from gently touches to push or beat, for preventing false alarms. You can easily set it according to your need.. These anti theft devices are great additions to home security. Battery operated alarm need 3pcs LR44 battery for each sensor for 1-year standby timing life. You do not need to change battery often. Low battery warning remind to replace the battery. Very easy to install and use, simple peel and stick installation (double-sided tapes included). No wiring or screws required. Mount the vibration detector on window and door or glass. Wireless vibration sensor with ultra-slim, lightweight design and pretty quality performance. Its perfect for your home, apartment, office, store, garage, dorm room, and also even car. Specifications: Material: ABS Color: Black/White Package Weight: approx.32g Size: approx.72x72x9mm/2.83x2.83x0.35in (More Size Detail, Please See Photo.) Note: Please allow 1-3mm error due to manual measurement. Please make sure you do not mind before you bid. Due to the differences between different monitors, the picture may not reflect the actual color of the item. Thanks! Package includes: 1Pcx Wireless Door Vibration Sensor Alarm