Developed by an orthopedist, this alternating-pressure inflating backrest stimulates circulation and flexes muscles to help alleviate back stiffness and fatigue. An internal air bag gently inflates and deflates to aid circulation to areas of the back that receive insufficient blood flow during prolonged sitting, relieving tired, sore muscles. The air bag also exerts a gentle pressure on back muscles and the spine, causing them to flex and reducing discomfort from inactivity. The slightly concave backrest promotes proper posture and provides support that's necessary for optimal back health. The tethered remote enables you to inflate and deflate the air bag manually, set it to inflate automatically every 40 to 90 seconds, and select the preferred amount of pressure. Powered by the included AC or DC adapter, the backrest fits in nearly any chair and is ideal for long road trips or those with sedentary jobs. 13 1/2" H x 12" W x 3 1/2" D. (2 1/3 lbs.)