Sound oasis sound cards are the world's only memory cards that allow sound machine owners to expand their collection of available sounds and music. By simply inserting the patent pending sound card, users can explore different parts of the world and experience a wide range of sound therapy. Each sc-300 series sound card contains our next generation playback technology for the clearest, most realistic sound quality available. The nature journey sound card takes you to soothing and relaxing environments to help you sleep and relax easier. It incorporates 12 authentic digital recordings of nature recorded in the wild by the world's more foremost nature recorder: thunderstorm, crashing waves, forest rain, waterfall, gentle surf, ocean rain, wind, secluded lake, caribbean surf, jungle stream, summer night, amazon lagoon. Works with the sound oasis s-650-01 and s-650-02 sound sleep therapy systems.