Individual sizes are specifically designed to target different areas of the body.Warms the muscles and helps release toxins which make them particularly beneficial for use before and after exercise and for individuals who suffer from poor circulation.Massage balls are designed to stimulate the deep tissue massage, blood circulation, pressure point, flexibility, and mobility. They are widely used treatment for releasing feet, back, neck and shoulder pain, as well as relieving tension.Alleviates tension and muscle knots by rolling over the affected area in repetition. These massage balls are made from durable PVC, which is firm enough withstand any body weight on it. They are durable for long lasting use and will provide perfect tension and great for those areas you can't quite reach with a foam roller. Set containers:6cm diameter 8cm diameter 10cm diameter.