Description: Keep linkage with SONOFF smart devices to create various smart scene Turn on/off your light with an action Notify you when the door/window is opened Check the opening and closing status of door/window on APP Battery-level display and low-battery reminder Allow sharing the sensor with your family to monitor and control of your home No gateway required Bluetooth low energy pairing Support to check history record on APP Low-power Wi-Fi transmission for more lasting work time Peel and stick installation, quick to use Specifications: Battery Model: AAA 1.5V; Working Voltage: DC3V (2 x 1.5V battery); Quiescent current: 40 A; Wi-Fi: IEEE 802.11 b 2.4GHZ; Material: PC V0; Package Included: 1/2/3/4/5 x Door And Window Sensor(not include battery)