Please read this before you buy 1. This sensor must match the xiaomi multifunctional gateway or Aqara gateway hub ( need to be purchased separately ) to use. 2. Aqara gateway hub is required to make this sensor to work with HomeKit. Highlights Original Aqara smart door and windows sensor for daily security ZigBee wireless connection Trigger and alarm: Connected with Aqara Hub, it will trigger alarm when someone break into. Away from home mode: Smart linkage with other smart home devices. If someone broke into, the bell will ring and the IP camera ( not included ) will take video. Can work with Apple Homekit, Mi Home, Aqara Home Small size, easy to install Specifications Model: MCCGQ11LM Battery: CR1632 (included) Wireless Protocol: Zigbee Dimensions: 41 22 11 mm (1.61 0.87 0.43 in.) Maximum Detection Distance: 22 mm Operating Temperature: -10~+45(14~113) Operating Humidity: 0 - 95%RH, non-condensing App: Apple Home app (iOS 10.3 or later), Aqara Home app (Android 5.0 or later, iOS 10.3 or later), Mi Home app Packing List Sensor Unit x 1 Magnet x 1 Sticker x 2 Quick Start Guide x 1 Aqara Door and Window Sensor Detects if a window or door is closed in real time. Peel & Stick | Local & Remote Alarm | 2 Years Battery Life * An Aqara hub is required. Smart sensor for every door and window Install the Aqara Door and Window Sensor on your door or window at home to always know if they are opened or closed. Do you often forget to close your doors or windows? Just use your phone to find out. Smart control in Apple Home app