Easily strengthen your muscles while having fun. Bring the small rotor inside the Rota Dyn Ball up to 10,000 revolutions per minute. This allows you to specifically train the muscles in your upper and lower arms, as well as your shoulders, chest, and hands. It can be used anywhere: in the office, at home, or on the go. Increase your performance and concentration effortlessly while enjoying yourself, whether for computer work or sports and leisure activities. You control the rotation speed: the faster you spin the inner rotor, the greater the forces exerted. With a weight of up to 15 kg, this provides a powerful workout. An effective fitness tool: in addition to its training benefits, the Rota Dyn Fitness Ball relieves tension and reduces stress. It also promotes blood circulation – a true all-rounder.