Detects vibration and movement at home, Wireless Automation, Local & Remote Alarm, Zigbee, can be placed anywhere according to your needs, guarding your home, When vibration, tilt or drop is detected, Aqara Vibration Sensor will trigger the Hub to sound an alarm and send a notification to your phone, can be used through HomeKit with the Aqara Hub.Dimensions: 36 x 36 x 9 mm Battery: CR2032