The Adidas core gym ball 65cm (25.5") is the ideal addition to your core, stability and flexibility exercises that forces you to maintain balance and thus enhances effects of your everyday workout. To keep the balance, the body is forced to use different muscle groups that wouldn't be active while exercising on a flat surface. The Adidas core gym ball is suitable for sit-ups, back exercises, stretching, balance and resistance work. It is designed for users who weigh up to 110kg (243lbs) and are between 5ft (152cm) and 6ft (1.83m) tall. It is also delivered with a hand pump.