The Sit On Air is a dynamic inflatable cushion which, thanks to its shape, has a double use. With its bump towards the external part of the chair, it stimulates the torso muscles which sustain the spinal column, promoting the maintenance of a correct posture. With its bump towards the internal part of the chair, it allows to lift the legs into a relaxing position. The movement and the provided beneficial effects are comparable to the benefits which are offered by the ball. A brochure with some exercises is included in the packaging.