4.5″ Vibrating Massage Ball Features: Choose from low, mid, or high intensity vibration modes Rubberized on/off area provides comfortable rolling surface (no hard plastic) Fully charge for 4+ hours of use Uses universal USB charger Made with non-toxic, latex-free, closed cell EVA/Polyolefin foam Benefits: Vibration stimulates muscles to increase circulation Offers both multi-directional roll and single point myofascial release Activates muscle recovery in the hamstrings, gluteus, hip flexors, calves and more Reduces muscle fatigue and tightness, promotes flexibility, and enhances performance