Sony D-NS921F Atrac3/MP3 CD Sports Walkman Stylish, ultraslim portable CD player compatible with MP3 files and Sony's ATRAC3plus compression technology Includes SonicStage CD Simple Burner software to facilitate ATRAC3plus CD burning from MP3 files and from other CDs Skip-free G-Protection technology eliminates or reduces skipping during many active uses Bookmark playback function for easy programming--recalls designated favorites from multiple discs 75 hours long playback with 2 AA batteries (not included) with ATRAC3 audio files