When shopping for a spy voice recorder you need to consider several features including the sensitivity of the microphone, format of the saved recordings and memory capacity of the device. This will ensure that you buy a product that meets your requirements.
While most devices save the audio recordings in MP3 or WMA format, experts recommend that you choose a voice recorder that also offers a WAVE file format. This format is simple, and you can easily make changes to the file. Furthermore, it offers very accurate and superior quality recordings.
The spy recorder should be energy efficient and should offer a recording time of at least 10 to 20 hours. In case you intend to leave the recorder in a specific spot and will not retrieve it for a long time, you should opt for a device that has an operating time of hundreds of hours.