The Chuango H4 Plus is a Wi-Fi alarm system. The smart hub is connected to your router. All individual sensors are connected to the hub. The hub receives a signal when a paired sensor detects trouble. All connected users then receive a push message on their smart device (iOS and Android). This way you always and everywhere know that there is danger at your home. The package consists of 2 remote controls, 2 magnetic contacts and a motion detector. In addition, the H4 Plus is compatible with Amazon Alexa. You can also integrate the Nest thermostat easily in the Chuango H4 Plus app.