Rechargable Covert Bionic Earpiece
The bionic earpiece is a blend of technologies but is fundamentally a form of hearing aid. You use it as if it was an audio amplifier like the toy spy ears, but the bionic earpiece has been designed to hide inside the ear much like an inductive earpiece. With a built-in sensitive microphone and powerful amplifier, you can hear distant sounds clearly and discretely.
The bionic earpiece has an adjustable volume control and a number of ear fittings. This allows you to tailor the earpiece to fit into your ear comfortably. The main unit is rechargeable, therefore saving you a small fortune in expensive batteries.
I would expect that this device has limited audio amplification, since it would be difficult to orientate the microphone in the direction of the target. I would prefer to use a directional microphone and then use earphones traditionally used with an MP3 player, such as an ipod. Just as covert, and much more flexible in an operational situation.
You can find the bionic earpiece on Gadget Universe.
Where and how could by this rechargable covert bionic earpiece
The link is at the bottom of the post.