Panasonic SL-CT520 Portable CD / MP3 Player with D.Sound Technology Personal CD player with anti-skip protection and wired remote control Supports CD, CD-R/RW, and MP3 formats; 6 equalizer presets for varied sound D.sound technology reduces distortion, boosts the bass, and restores lost MP3 fidelity Plays up to 155 hours (MP3) or 86 hours (CD) on 2 AA and 2 AAA batteries Includes external battery case and headphones; 5.38 x 0.78 x 5.38 inches (W x H x D)