Questions about Vluv Leiv

Size 65. I am 1.60m tall and have a normal desk. However, the ball always rolls towards the tabletop despite the retaining ring at the bottom. That bothered me in the long run. But it is still very much in use in our household.

The set is delivered uninflated but can be inflated with any standard car, inflatable boat or bicycle pump. Unfortunately there is no pump included in the delivery.