Shelly Blu Door/Window Black is a Bluetooth-operated sensor, with a long-lasting battery of up to 5 years, that can measure tilt angle and luminosity. It has a compact and stylish design that allows for easy installation on doors, windows, safety gates, garage doors, and more. PROTECT YOUR HOME, EVEN WHEN YOU'RE AWAY - Always be informed of any unwanted guests! Simply place Shelly BLU Door/Window on your front door, balconies, windows, or garage door, and receive a notification if someone opens them while you are away. But thats not all! Shelly BLU Door/Window can be used as part of your security system using automation scenarios or scenes. LET NO ENERGY GO TO WASTE - Shelly BLU Door/Window can also contribute to your energy efficiency efforts. By connecting it to other devices, you can automate the adjustment of heating, cooling, or lighting based on the door or window's open state. For example, when a window is opened, the system can automatically turn off the heating.