Product Features: 1. Instant Notification: Push instant notification to your phone immediately when door or window is opened or closed. Keeping you informed all the time. 2. Alarm Alert: Whenever the sensor is triggered to open/close, it will send alarm to alert you that someone opens your door or window. 3. Alarm Recording: Support checking open / close records and battery level on the app. Never worry about missing any important moments or running out of battery. 4. Device Share: Select "Home Management" in the "Me" page to share your added sensors with family members. so that they can also monitor the status of doors/windows. 5. Low Voltage Remind: When battery level is low, it will automatically remind you to change batteries, never worry about running out of battery. Works with amazon alexa and Google Assistant. Colour: Black Material: ABS Package Contents: 4 x Main Body 4 x Small Body 4 x glue 4 x English User Manua