NOTES: An Aqara Hub is required and sold separately. Requires a secured 2. 4 gigahertz WiFi network connection. The Aqara M2 or M1S Hub can connect up to 128 devices(*use of a repeater such as the Aqara Smart Plug or Aqara Smart Wall Switch(With Neutral) is required). UNAUTHORIZED ENTRY DETECTION: Whenever the door/window opens unexpectedly, the Aqara Door and Window Sensor will send an alert notification to your phone and activate the local alarm on the Aqara Hub. HOME AUTOMATION: The Aqara Door and Window Sensor can control other Aqara connected devices as the status of the door or window changes. 22MM WIDE GAP ALLOWED: The Aqara Door and Window Sensor works with most types of doors, windows, and other fixtures with similar mechanism, such as drawers, cabinets, and more. VOICE CONTROL: Compatible with Apple Home Kit, Alexa for a hands-free experience. In addition, If you have any questions, please feel free to contact us.