This is the metronome light system that trains you to relax your mind and body so you can drift off to sleep quickly and naturally. About the size of a smoke detector, the cordless unit projects a hypnotic blue light onto the ceiling. As users focus on the light, its frequency gradually slows from 11 to six breaths a minute, a meditative technique used by yogis for millennia to encourage relaxation. Ideal for combating jet lag or for those with irregular sleep schedules, the device offers an effective alternative to drugs without any side effects. With 8- or 20-minute sleep cycles, automatic shut-off, and adjustable brightness. Includes three AAA batteries. 4 1/2" diameter x 1 1/2" D. (8 oz.)