Phone
Bugging .com
Range up to 1500 feet in open area .
Operates by 9-volt alkaline battery, (not included) the transmitter can operate up to 24 hours.

In this example the transmitter is concealed in a cigarette package . In the same way you can hide it in any other common package.
This concealed transmitter is sensitive enough to pick up even whispers from any part of the room.
The transmitter is high - reliability fm modulated hybrid circuit.
Frequency operation is 433 MHz crystal controlled FM narrow band.
No antenna required . Audio bandwidth: 20 Hz to 30 kHz .