Sony LBT-GTZ4i 3-Disc CD Changer Mini Shelf System with Play Exchange (Discontinued by Manufacturer) Z-groove: rich, deep bass from all connected sources 3-disc CD changer with play exchange CD-R/CD-RW and MP3 playback Dual USB ports: record and playback (MP3, WMA, AAC) Made for iPod - charge, play and control Audio-in for use with MP3 player or PC Made for iPod - charge, play and control Dual USB ports: record and playback (MP3, WMA, AAC) Audio-in for use with MP3 player or PC 3-disc CD changer with play exchange CD-R/CD-RW and MP3 playback Z-groove: rich, deep bass from all connected sources