Sony D-NE510 ATRAC3/MP3 CD Walkman 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 40 hours long playback with 2 AA batteries (not included)