RING Alarm Contact Sensor (2nd Gen) - 2 pack Get real-time notifications the moment a door or window opens in your home. Now with a more compact design and a slim removable magnet for easy installation, even when space is limited. Requires Ring Alarm Base Station. Compatible with 1st and 2nd generation Ring Alarm devices and accessories. Depth: 35 MM x2 Ring Alarm Motion Detector - 2nd Generation Battery - 2x CR2032 Lithium Coin Cell 3V batteries. Connectivity - Z-Wave (76m range to Base Station open air, line of sight). Mounting - Mount to door or window frame. Maximum distance between sensors - 2.54 cm. Height: 47 MM Width: 81 MM