ITEM NAME:2Pcs Fitness Massage Ball Lacrosse Balls Epp Foot Relax Relieve Fatigue Gym G4G3 2Pcs Fitness Massage Ball Lacrosse Balls Epp Foot Relax Relieve Fatigue Gym G4G3 Colour: Black Material: EPP Diameter: 10cm Fitness effect: 1. You can do the same with your back. Because of the soft force, yoga ball movement is relatively safe, even those who have injuries on the back and need rehabilitation treatment can also practice, can avoid excessive impact on the joints, it will be a lot easier to do. 2. Train the balance of the human body. The yoga ball is an "unstable" exercise device. When you leave the ground with a yoga ball, you must try to maintain balance, not let the ball roll, nor let yourself fall from the ball. This requires legs, waist, and abdomen. Comprehensive strength control, which is good for maintaining body coordination and muscle strength. 3. Massage effect. The yoga ball moves as much as possible to make the body fully contact with the spherical surface. The yoga ball is made of EPP material. When the human body comes into contact with it, the yoga ball will massage the body evenly and gently, which is beneficial to promote blood circulation. 4. Correct the posture. As you sit on the yoga ball, the body is constantly making small adjustments to keep the body stable. These small movements can promote blood circulation, strengthen the back and abdomen strength, let you sit up involuntarily, open your shoulders, and correct your long-standing wrong posture. Package Contents: 2pcs Fitness Massage Ball.Material: EPP. Massage effect. The yoga ball is made of EPP material. Train the balance of the human body. The yoga ball is an "unstable" exercise device. When you leave the ground with a yoga ball, you must try to maintain balance, not let the ball roll, nor let yourself fall from the ball.