Now with a more compact design, Ring Alarm Contact Sensor features a removable slim magnet for easy installation on any door or window frame, even when space is limited. With a Ring Alarm Contact Sensor installed you can choose to get audio or mobile notifications whenever a door or window is opened. New compact design blends in seamlessly with your home. Easy, tool-free installation, Mounts to doors and window frames. Requires Ring Alarm Base Station (sold with Alarm Security Kit). Alexa compatible. Compatible with iOS and Android operating systems. Suitable for indoor. Batteries required 2 x coin cell (included). Size H4, W5.3, D1.4cm. In the box: Contact sensor, slim magnet, quick start guide. Manufacturer’s 1 year guarantee. EAN: 840080561172.