Panasonic SV-SD85 e-wear SD Audio/MP3 Player with 128 MB SD Memory Card Ideal for sports -- will not skip as it contains no moving parts 18 hours playback time with supplied Ni-MNH rechargeable battery Includes 128MB SD Card -- infinitely upgradeable with additional optional cards High quality sound via built-in MP3, WMA ( Windows Media Audio ) and AAC decoders Frequency Response - 20Hz - 20kHz (+0 / -6dB)