I am already for years a "Swopper" fan, but he is only 12 years and the "Swoppster" for the younger ones had me then too expensive for the start of school.
An exercise ball with "Antiwegrollschale" is perhaps difficult to regulate even a cheap alternative on the size and distance from table and rather bulky.
Although my son is one of the smaller school starters, he gets on well with the lowest setting height. That had rather put me off when browsing in other reviews.
So we are all highly satisfied and no one has to like a pencil pusher with homework stick to the chair.
The back would be !!