The Shelly BLU Door/Window has a huge range of applications, ranging from security/burglary deterrence by providing instant updates when any movement is detected to being used in wider scenes such as adjusting lighting when a door is opened or closed, or adjusting heating and cooling based on whether your windows are open. This sensor features a 5-year life on a single battery and is rapidly responsive, with an average response time of less than 100ms. The Shelly BLU Door/Window is also designed to have a low aesthetic profile, blending seamlessly into its surroundings, and its compact chassis makes it easy to fit into any door or window. ***PLEASE NOTE: this product comes with the required battery (3V CR2032) and 3M 9448A Double Sided adhesive pads for wall mounting.