Give yourself relief with the 3.5 inch Large Massage Ball. Using the ball’s sensory spikes and your own body weight, release muscle knots, stimulate circulation, relieve stress, promote healing and boost your immune system. The Large Massage Ball is effective for working out tension in the shoulders, pecs, calves, hamstrings, abdomen, buttocks, upper and lower back, deltoids and neck. Place under these areas when sore or knotted and allow the gentle spikes stimulate circulation relieve pain.