Plays audio files in MP3, WAV and WMV formats; proprietary technology maximizes volume at the ASHA-recommended 85dB level for hearing safety. Built-in microphone records podcasts and vocal responses, tracks student progress and is ideal for testing. 512MB of internal memory can be upgraded to 2GB of added memory. Handheld, ABS-plastic unit features volume and playback controls, equalizer, power-saver setting, bright backlit LCD with multiple display features and more. Dual 3.5mm jacks connect up to two headphones at the same time; includes one set of adjustable, volume-control headphones with ambient-noise-reducing ear cups. USB cord transfers tracks to and from your computer (PC and Mac compatible) and recharges the internal battery for up to 16 hours of continuous play.