Revolutionary Automatic Foam Roller System, the perfect combination of classic and involution. 3- Speed design: choose between low, medium,and high intensity to apply the perfect amount of pressure to each of your sore muscles and joints, relieve muscle pain. The yoga roller measures 6" in diameter and 13" in length. our simple included wall-outlet charging cable makes it easy to get a massage anytime, anywhere. One full charge will give you over two hours of vibrating massage!