Use door/window sensors to protect anything that opens and closes, such as doors, windows, jewelry cases, and gun cabinets. The sensor detects intrusion with a magnet and reed-switch mechanism that signals an alarm during unauthorized entry. Features: Installs on anything that opens or closes For low and average traffic areas Specifications Magnet included Color: Brown Dimensions: 1.13'' wide, 4.25'' high, .88'' deep Batteries: 2 AAA alkaline