● App controlled by 4G Cellular data, no need WiFi router. ● Max connecting 50pcs wireless detectors/sensors, and 8pcs remote controllers. ● Max supporting 6 groups alarm phone call and 6 groups SMS numbers. ● The names of each defense zone can be edited. ● Low battery alert of the accessories. ● Program the defense zone into immediate, delay, 24hours, doorbell , elder zone,bypass model. ● Built-in rechargeable battery power ON/OFF alert. ● Built-in 9 different languages. Click for more info: https://www.alibaba.com/product-detail/Factory-price-Tuya-smart-home-wireless_1600612466156.html?spm=a2747.product_upgrade.0.0.3e0a71d2PREfye