Sit On Gym Balance Ball
This seat is a gym ball that can double up as a therapy ball for core stability work.
It provides less support than the fit chairs, and will allow tipping back.
It is more suitable for a student who has a good understanding of their needs and is able to limit the movement that they produce when sitting on a ball. Colour may vary.
Not able to let you know personally about ball but the teacher who ordered them seemed to be pleased on receipt.