Eyetek's two-way adapter may seem innocent, but it also functions as a hidden recorder.
Activated through voice-recognition technology, the digital recording system is completely hidden under a functional mains-powered unit. Recordings are stored on a Micro SD card, and the amount of information you can store is only limited by the size of the card you use, up to 32GB; in other words, 24 days of recording time.
To stop you having to dig through hours of silent footage, the recorder will only begin when activated through sound-recognition sensors in the target area.
Small as they may be, they will hit your pocket hard with a price tag of £225 ($360).