Twist your way to greater fitness! As you twist back and forth on this rugged aerobic disk, you'll tone your abs, hips and back muscles and increase blood circulation while building core strength, stability and endurance. Built-in magnets and acupressure nodes gently massage the soles of your feet, easing stress while helping you stay centered. Larger than other twist boards, with more ball bearings for smoother gliding. Poly-vinyl. 12" in diam. x 2" h. 250-lb. capacity.