This is the device used by the Duke Medical Center to help patients reduce their stress and anxiety without medication. Synchronizing your breathing with the rise and fall of the device's illuminated LEDs and audible cues has been shown to slow heart rate, improve relaxation, and reduce stress in as soon as five minutes. Relying on the same breathing techniques taught in yoga for relaxation and stress reduction, the relaxation coach takes a pulse reading from your thumb or earlobe and instantly develops a rhythmic breathing sequence for you to follow. About the size of an MP3 player, the device stores unobtrusively in a pocket, allowing convenient use before any potentially stressful event, such as a business meeting or prior to boarding a plane. Rechargeable battery lasts up to six hours after a three-hour charge. 3 1/3" L x 2" W x 1/2" D. (2 1/4 oz.)