GoolRC GSM Door Gate Opener Remote Control Access Controller

*850/900/1800/1900MHz quad bands, can work in worldwide GSM networks. color:#c0392b;*No call charges. GSM Relay Switch answers call from authorized number then carries out turn ON/OFF on first 'ring'. *Secure - Using caller-for identification, unknown callers are ignored. *Add or remove users by SMS Text command. *No need to provide a remote control or keys for different users.