Smart Wireless Door ContactSmart Wi-Fi Wireless Door or Window Contact, which works with one small battery (included) that can last for approx a year. Get notifications on your smartphone as soon as door sensor is triggered. Make your door/window smarter, when you leave home, it will push notification to you if the doors or windows are opened or invaded by an external boject, you will find anomalies in your home immediately.Battery Wi-Fi powered, full of power long durable, replace the battery is simple,service more intimateProvides remote home monitoring.Very Small and Elegant design, makes your home look very stylish.Plug and Play with enerjsmart app, No hub required, simple download the "enerjsmart" app on iOS and Android.Technical Specifications:It supports Bluetooth: V4.1 and above.It is IPX4 Waterproof.It can be connected with 2 devices.It has CVC 6.0 noise reduction.It charges fast and has play time up to 4 hours.It comes with a power display and inbuilt Mic.It has auto connect