This heated lumbar cushion adjusts to your preferred level of firmness, encouraging proper posture and relieving sore, stiff lower back muscles. The pneumatic cushion expands and contracts via the controller, allowing you to quickly customize the curvature for optimal support. Carbon fiber heating elements inside the cushion generate 104º F to 134º F heat that relaxes tired lumbar muscles and joints that tighten during prolonged sitting. The cushion is lined with 1/2" of soft foam that contours to the shape of your back and relieves pressure points. The cushion clips onto a chair's backrest (up to 14 1/2" thick) to accommodate users of any height. Plugs into an AC or automobile outlet (adapters included). 19 1/4" L x 11 1/2" H x 1 1/2" D. (1 3/4 lbs.)