eufy Security, Entry Sensor, Detects Opened and Closed Doors or Windows, Sends Alerts, Triggers Siren, 2-Year Battery Life, Indoor-use Only, Requires HomeBase S280 or HomeBase S380

2-year Battery Life: One battery provides 800 days of monitoring. For Doors And Windows: Compact and versatile design fits onto any door or window frame. Requires eufy Security HomeBase. 100-Decibel Siren: Enable or disable siren protection, which triggers a 100-decibel siren on HomeBase, and sends an alert to your smartphone when forced entry is detected. Easy Installation: Just peel off the mounting tape and stick or screw the sensor onto the door or window you want to monitor. What’s Included: Entry Sensor, CR123A Battery, Magnet, 3 x Mounting Screws, Owner’s Manual, Happy Card.”