Connectivity: Up to 20 sensors and 10 SOS buttons. Radio Frequency: 433MHz. Help Button Body Protection Level: IP65. Back Battery: 3.7V, 500mAh Lithium Battery. Band(only for 4G model): LTE-FDD B1/B3/B5/B7/B8/B20,GSM/GPRS/EDGE 900/1800MHz@A7670E module.
