This is the clock that uses light and sound therapy to help reset the body's regular sleep patterns for falling asleep easier at night and waking with a more rejuvenated feeling in the morning. Known as the body's internal clock, the circadian rhythm responds to light levels over the course of a 24-hour cycle, causing one to sleep or wake up. The clock's light panel uses 70 white and 30 blue LEDs that decrease or increase in intensity to simulate dusk or dawn--a Harvard Medical School study revealed that blue light can immediately improve alertness in the morning. It can also plug into a desk lamp, dimming its light at dusk and brightening at dawn. Fully customizable, the clock's sleep and wake time intervals of 5, 15, and 30 minutes match waxing and waning light levels with music played from its FM radio, MP3s played from the included USB memory key (with eight nature soundtracks) or MP3s played from its SD/MMC memory card slot. Music can be set to a preferred volume, which decreases at bed time and increases near dawn. The full-range 5-watt speaker provides crisp, unmuddied sound; includes headphone jack. Plugs into AC. 9 3/4" W x 5 1/4" D x 6 1/2" H. (5 1/2 lbs.)