This is a unique and brilliant telephone surveillance device.  Perfect for negotiations being conducted over the phone.  Simply attach this to your phone.  During a conversation you tell the person that you are talking to that you need to put them on hold for a short while.  Whilst the other party thinks they are on hold their telephone has, in fact, been turned into a super-sensitive listening device.  The unit even gives a ‘call waiting’ sound and you will be able to hear what they are saying.

Originally designed in the U.S.A. for use by Federal Investigators.  Powered by 1 x PP3 (9V) battery – included.