Smart Wireless Door Contact Features: Smart 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 intimate Provides 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 Specifications: Dimensions: H:2.2 x W:2.1 x D:7.1 cm Colour: White Guarantee:1 Year Material: Pvc Model Number: SHA5265