It features 32 MB of built-in memory, and is expandable using MultiMediaCards (MMCs). The DUO-MP3 plays MP3 digital audio files, and can also play Windows Media Audio (WMA) files with a firmware upgrade.

DUO players can also play content from Audible.com, the Internet's largest, most diverse provider of premium spoken word audio for download or playback on personal computers or AudibleReady mobile devices. Audible Inc. has more than 28,000 hours of audio programs and 160 content providers, so you can use your DUO player to listen to a daily audiodigest of the Wall Street Journal, weekly digests of the Economist and Forbes, and audiobooks that aren't available anywhere else.

With its adjustable head control, you can optimize the DUO-MP3 for different cassette decks, enabling maximum compatibility and audio fidelity. The rechargeable NiMH battery allows you to enjoy uninterrupted music for up to six hours and up to nine hours of spoken word. Its USB connection enables fast download speeds, while the sleek aluminum body provides the utmost in portability.

To help manage music, the DUO-MP3 comes with RealJukebox music management software from Real Networks. Convert CDs, index your files, and create custom playlists.