Listen through walls with a wall microphone or covert audio transmitters that utilize rf (radio frequency) or UHF signals.
Some of these signals can travel up to 1 kilometer (5/8 mile).
There is a variety of covert audio spy equipment available that allows you to hear what they are saying and this includes some of the following:
Telephone transmitters, ear phones and voice transmitters (hidden in pens, cards, calculators, outlet adapters, telephone outlets etc.).
Plug in your earphones, stick the microphone up against the wall and hear conversations taking place in another room.
This microphone can hear through walls and virtually any other surface like windows, concrete, steel, etc.
It can also detect leaking pipes and even the faint sound of a bomb ticking!
A 9 Volt battery is included and the charge capacity is 60 hours.
If you need to listen through hotel walls (or motel), it's not a problem, as listening bugs like these can easily listen through a standard 5 star hotel wall.
Use it at home, office buildings or any other place that you might need it.
It is advised that you check with the laws in your country or state before you order these type of devices or other covert audio transmitters.
Utilizing a wall microphone and other wireless rf audio transmitters can be very useful during surveillance operations.