8PCS SONOFF DW2-RF-433MHZ Sensor Door Window Alarm Sensor RF 433Mhz Wireless Automation Anti-Theft Alarm Compatible With RF Bridge For Smart Home Security Alarm System Overview: SONOFF DW2-RF-433MHZ Sensor is a door and window alarm sensor. The door alarms can work with Sonoff RF Bridge 433. SONOFF DW2-RF-433MHZ door alarm sensor detects the opening status and immediately sends alarm notification message to the APP.  Features: *Send the alert to your smartphone when the door/window is opened. *Open the door to trigger lights on/off. *Compatible with IFTTT service to set more routines. *Share the sensor to make more users know the status of home. *Can check history records last 3 months. *Low power consumption technology maximize the battery life - up to 2 years. *Easy to install and remove. Specifications: Support Battery: 12V 27A  Wireless frequency: 433.92MHz Protocol: EV1527 Quiescent current: ≤1.5μA Emission current: ≤20mA Operating environment: -10℃-50℃ (14℉-122℉) Battery type: Alkaline battery (Note: this model doesn't come with batteries) Packing List: Sonoff DW2-RF-433MHZ Sensor (1/2/3/4/5/6/8/10PCS Optional)