Studies have shown that we sleep better and relax easier when we can block out distracting noise and listen to natural sounds. Sound oasis sound machines are used in hospitals, clinics and in homes around the word to help people fall asleep easier, experience higher quality sleep and provide relief from tinnitus. By bathing your room with our #1 rated nature sounds, the s-560-03 provides effective, natural, prescription free sleep therapy. It also includes a jumbo alarm clock so you can wake to a buzzer or nature sound. For extra sound variety, add more sounds with our patented sc 250 series sound card system. Product features: 6 professional quality authentic nature sounds: ocean surf, stream, rain, white noise, summer night and wind. World's only sound card technology for adding more sounds (see available optional sound cards). Jumbo alarm clock with buzzer or nature alarm. 4 position auto shut toff timer: play sound continuously or auto shutoff gently after 30, 60 or 90 minutes. Memory button repeats last sound experience. Headphone/speaker jack. Powered by ac adapter (included) or 4 "aa" batteries (not included). Omni directional reflective speaker projects sound from the back of unit for rich, deep sound. Use upright, on its back or mounted to a well. Uses sc-250 series sound cards only. One size.