So you would like to record audio discreetly? This tiny USB Voice Recorder can help. It can record at 192kbps with a range of up to 50 feet. It supports 20 hours of continuous recording. The device has 16GB memory, enough for 5000 songs. It has 3 buttons for easy control.
The Snahike Audio Recorder has a battery life of over 95 hours.
[where to get it]