4GB Silver Missile USB Flash Digital Voice Recorder Pen with MP3 Function 503 is not only a pen which can write smoothly, but using such a well disguised recorder pen to record something importable would certainly easier than using the common devices. This pen like voice recorder has a 4GB built-in flash memory card and rechargeable li-ion battery, so you can use it to record for a pretty long time and record as much as you wish. In leisure time, this pen is no longer a digital voice recorder but only a MP3 player with which you can enjoy various songs of MP3, WMA, ASF, and WAV music formats.