Our massage ball adopts double ball design, which perfectly fits the muscles of back and shoulder.By rolling back and forth, the fascia and muscles are stretched and released, and muscle soreness is alleviated. Use the body's own strength to roll back and forth and strengthen local massage, which effectively relieves muscle groups and allows the user to enjoy the feeling of being massaged. Excellent design and easy to relax your muscles by yourself. Back :to reduce tightness in neck and shoulder muscles Legs : to relieve muscle tightness due to a prolonged time in a standing position Arms: to and relax muscles Waist & abdomen: to stretch and relax after sedentary posture in office Buttocks: to alleviate the stiffness and discomfort caused by sedentary posture Our massage ball is made of Rubber, which is durable and environmentally friendly material. it is durable for long-lasting use. Extremely multipurpose:It's very easy to relieve tennis elbow, stiff neck, tight shoulders, sciatica, manipulation of both sides of the spine and more. Colour:yellow Material:rubber Size:14 x 6.6cm Package Contents: 1 * Shape Massage Ball Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.