These spiky massage balls use the pressure of your bodyweight to ease muscle tension and reduce stress. Place them under sore, knotted muscles and lie back as the nubs stimulate sensory points. Massage balls help improve blood circulation in stiff muscles and promote healing. With 2 sizes, address problem areas like feet, shoulders and back, enhancing muscle performance and reducing risk of injury. Small and lightweight, they are excellent self-care tools that easily fit in a suitcase or carry on.