Developed as a result of U.S. Air Force research to improve F-16 pilots' ability to withstand extreme g-forces, this device can reduce your blood pressure without medication. University studies correlate the handgrip trainer's isometric exercise to the calming of the user's sympathetic nervous system, the reduction of their resting heart rate, and lowering of their blood pressure. Clinical research by cardiovascular specialists shows the device lowers blood pressure in more than 90% of users who perform the therapy 12 minutes per day, five days a week. Simply hold the device and squeeze as hard as you can; the unit measures your maximum hand strength and calculates a target pressure. The handgrip then prompts you to maintain the target pressure, indicating when to squeeze harder or loosen your hold with audible tones and visual cues on the LCD. The therapy can be performed while reading or watching television and positive results are measurable in four to eight weeks. Includes one CR123 battery. 5 1/4" H x 3 1/4" D x 1 1/2" W. (5 3/4 oz.)