This voice activated GSM bug gives you the ability to dial into the unit and listen in to surrounding sounds with startling clarity. The bug can be programmed by SMS commands to dial any number you choose when it detects sound or speech, ensuring you don’t miss that important conversation. The intelligent GSM Bug operates on the GSM frequency 1800 and 1900MHz communications network for worldwide coverage. The sound activation function can be switched on and off by SMS commands, of course you can dial into it at any time. This unit contains a 5,200 Mah Li-Ion battery giving it upto 6 weeks battery life in standby.