An air-filled and secure ball made of Crylon. The material is odorless, latex-free, very resilient up to 500 kg (guaranteed space security if the outer skin is damaged up to 90 kg) and made of 100% recyclable plastic.Strengthening the abdominal, back and whole body muscles through safe, effective and dynamic back and stability training. Can help or alleviate back problems by sitting upright and moving.When sitting on the ball, an upright posture is automatically adopted so that it does not fall off the ball. At the same time, the pelvic, abdominal and back muscles are involuntarily used to balance the ball while sitting. Instructions are included in the product packaging with specific exercise suggestions.In the event of damage from objects such as sharp edges, needles, glass splinters, scissors, etc., the material of the ball skin prevents it from tearing open suddenly. The air escapes slowly through the hole. A burst is impossible and injuries due to an unexpected fall are avoided.