Questions about Topstar Sitness 20

I'm sorry I can't answer that, only this: I love this chair and would never give it away again.

There is none there either. The description text is wrong.

There are still a few differences in the material and there are two different suppliers who ship the chairs. Here you can see it a little better https://www.galaxus.ch/de/Comparison/5799796-5799811

Yes, the maximum seat height of the Sitness 20 office chair is 51 cm.

Thank you very much for your advice. Double is better. We will correct this immediately. :)

As far as I know, any normal bicycle pump

Yes, this stool rotates on its own axis and you can easily turn left, right or all around.... Thanks to the "air pneu" foot, I sit very comfortably and can rock on all sides if I feel like it. Super stool and highly recommended.

I don't work in a nail salon or anything, but sit at a PC all day. The seat has helped me a lot with back pain and I still use it alternately with the "normal" office chair and the standing desk. However, the seat is not very comfortable. If you sit on it for several hours, your backside hurts (at least for me). But for me, the purchase was worth it.

The seat height is 39 - 51 cm, so it is also suitable for "taller children". :)