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 Note: SONOFFDW2 is now available for pre-order and shipped on May 20. Specification of SONOFF DW2 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; Download Center User Manual Specifications: Specification of SONOFF DW2 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; Download Center User Manual Package Included: 1 x Door And Window Sensor(not include battery) Notes: Due to the difference between different monitors, the pictures may not reflect the actual color of the item. Compare the detail sizes with yours, please allow 1-3cm error, due to manual measurement. Please leaving a message before you give the bad feedback,if the products have some problems. Thanks for your understandings.