GSM Bug Wall Clock. This modern style wall clock may be hung on a wall in a room of your choice. You can then dial the number of the GSM bug built into the rear of the clock – the call will connect silently after two rings anywhere in the world. This device also offers a voice activation feature that allows it to call you when it detects sound. Battery life on standby is around 6 weeks, this will be shortened depending on how long and how often you dial in.