Wireless GSM RTU5024 Gate Opener Relay Switch Free Phone Call Security Alarm System For Automatic Door GSM Opener Garage Defend ,Easy to Operate

> Quad-band, can work in the worldwide GSM Networks; > No call charges. the GSM GPRS Relay Switch rejects the call from authorized number then carries out the turn ON/OFF action on the first 'ring'; > Multiple applications. (gates, bollards, barriers, garage doors, shutters and access doors or machines); > Secure - Using caller-ID for identification, unknown callers are ignored; > Can be operated from anywhere, no distance limit;