Drives away painful knots. The staggered, vigorous beating action from the dual heads releases muscle tension and knots without being overly forceful. Variable 2 speed control lets you go from relaxing to invigorating in a snap. Great for the neck, shoulders, back, quads, hamstrings and more. With interchangeable massage heads. Knob, accupoint and figure pressure attachments, for a customizable experience. Runs on household current. Approx. 16 inches x 5.5 inches x 5.5 inches.