Eufy Smart Security Entry Sensor | T89000D4Protect Your Doors and Windows from Break Ins with eufy Security Entry Sensor. Once a window or door is ajar by 1. 5 inch, an alert will be sent to your smartphone, and a 100 decibel siren will go off on the HomeBase (can be disabled). 2 Year Battery Life: One CR 123A battery provides monitoring for 730 days. For Doors & Windows: Small and compact design fits onto any door or window frame. 100 Decibel Siren: If a forced entry is detected, a siren as