Revolutionary digital music-on-hold playback system supports MP3 and WMA audio formats. The unit has 16mb of on board memory preloaded with over 57 minutes of great sounding licensed music content, so its ready to go right out of the box. Add new content to the player by connecting to a PC via the USB port or just slip in a Smart Media card with new content. By adding a Smart Media card you can increase the memory to 128mb and over 9 hours of content! Best of all, there are no moving parts to break or wear...non-volatile memory means it retains its recorded content, even after power failure.