From Hydrogenaudio Knowledgebase
It featured 20GB capacity, FLAC, MP3, Ogg Vorbis and WMA playback. Until the release of the Rockbox alternative OS for DAPs, it was the only DAP capable of perfect gapless MP3 playback. It also featured excellent sound quality, parametric equalizer, an intuitive user interface, about 15 hours of battery life and other advanced features not found on most other DAPs. However, Rio Audio has discontinued the Karma as it is no longer sold by major retailers and Rio Audio's site itself. You can still purchased a Rio Karma used on popular trading websites like EBay despite the fact that it no longer marketed for cheap and with no warrenty.