Unlike Brickhouse Security, we won't go so far as to call this thing "invisible," but when placed in the ear, all but the most eagle-eyed among us are likely to overlook it. The elaborately named Secret Service Invisible 2-Way Micro Headset comes with an easily hidden wireless transmitter that plugs into any mobile with a 2.5-millimeter audio output. Once rigged up, the wearer can have someone listen in on conversation in a room while also receiving input from said listener. Unfortunately, this likely Jack Bauer-approved gizmo demands a practically ludicrous $649.95, so it looks like we'll be sticking to brute force and walkie talkies here. Check out a demo video after the jump -- but be sure and kill the speakers first, alright?