Have no idea whether burglars break into your home in your absence? Have you ever imagined that your home lights up at once when you open the door? Or wanna your bed-room light turns off automatically once you walk into the living-room? Any of your ideas will be reality with SONOFF DW2-Wi-Fi wireless door/window sensor. DW2-Wi-Fi comes in two pieces, the transmitter fits onto the door or window and the magnetic switch attaches to the frame. It can help secure your door or window to let you know whether your home is safe wherever you are. The sensor will trigger an alarm to your smartphone to remind you of an intruder when the door or window is opened.Keep linkage with SONOFF smart devices to create various smart sceneTurn on/off your light with an actionNotify you when the door/window is openedCheck the opening and closing status of door/window on APPBattery-level display and low-battery reminderAllow sharing the sensor with your family to monitor and control of your homeNo gateway requiredBluetooth low energy pairingSupport to check history record on APPLow-power Wi-Fi transmission for more lasting work timePeel and stick installation, quick to useSpecification of SONOFF DW2Battery Model: AAA 1.5V;Working Voltage: DC3V (2 x 1.5V battery);Quiescent current: ? 40 μA;Wi-Fi: IEEE 802.11 b 2.4GHZ;Material: PC V0;