You are purchasing a very small LPFM Audio Transmitter also known as a Spy Bug Audio Transmitter.  This is an easy to use, highly sensitive wireless audio transmitter that has an ADJUSTABLE OPERATING FREQUENCY which covers the FM broadcast band making it tuneable on a standard FM radio. 

When used in it's smallest form with a 9 volt battery, the battery will last 17 hours of constant use.  The receive range is up to 300 meters or 1000 feet.  Dimensions without 9 volt battery: 23mm x 11mm x 9mm

When used with the included 2-D battery holder, the batteries will last up to 74 days of constant use.  The receive range is up to 100 meters or 325 feet.  Maximum dimensions with installed battery pack: 80mm x 72mm x 30mm

Battery consumption was based on using Duracell or Energizer alkaline batteries and calculated using the Battery Life Calculator found here, http://oregonembedded.com/batterycalc.htm  .

We include a download link for the instruction manual.

• Real Time Live Monitoring
• Fully Assembled and ready to use
• The signal can be received by a standard FM radio, no special equipment necessary
• High sensitivity---can hear a whisper from a distance

Potential uses include:

• Surveillance
• Communications
• Baby / Child Monitor
• Wildlife Monitoring

And Much, Much more...   Review your state / country laws as use of this device may be illegal for some purposes.

EBay Staff: This is a listening device not capable of recording and thereby not illegal.