* Sound Oasis Sound Cards offer unlimited sound environment possibilities with the world"s first and only memory cards that allow sound machine owners to expand their collection of sounds. * Sound Oasis Sound Cards contain our next generation playback technology for the clearest, most realistic sound quality available. * For use only with Sound Oasis Sleep Sound Therapy System S-550-05. * Sounds included: Thunderstorm in the Wilderness, Loons on Wilderness Lake, Mountain Valley Windstorm, Forest Rain, Waterfall and Roaring Bonfire. .