Headsets for mobile phones are quite common, so it makes for a perfect place to sneak in a video camera. The spy camera here resides in a fully functional Bluetooth headset, so you can really use it, and let it be examined, in case anyone gets suspicious.
The recorder stores audio and video on its internal 2GB of memory, and there is a 2.4 inch display on the base unit to allow for stealth in the field review. The unit records in MPEG4, and it runs on a rechargeable battery.
As far as I can determine, there is a wire that runs from the clip portion to the recorder, so the audio video portion is not wireless, just the phone portion. But it is quite convincing. You can find the Spy Bluetooth Camera at Brando for $269.
