What is Sit Dome? Sit Dome is a chair seat cushion designed to provide the benefits of a ball chair while blending in with any kind of office décor. Sitting on an exercise ball during the workday can help improve posture, strengthen core muscles, and reduce fatigue, but it can look out of place in an office environment. Sit Dome will convert an ordinary office chair into a ball chair, and it can be customized with a variety of covers and colors to seamlessly blend into any work environment. Simply place the inflatable Sit Dome base on the chair, add the fabric cover of your choosing, and lock the clasp. Sit Dome features a unique hinged design that holds everything securely in place while also making it easy to swap out different covers as desired.