@BestofTimes Interesting review, thanks! It sounds as if I would like it, but as a short person with proportionally short legs, I would definitely need the short gas strut version. I use a Swopper stool at work (left over equipment from a friend's PhD student's project). It has no back or arms, and quite hard padding on the seat. It has a springy, wobbly post, and the idea is that you set it quite high so that you have an extended angle between your torso and thighs, and you 'manspread' your legs to provide stability. I enjoy using it, but it definitely becomes uncomfortable after a while and you need to get up and move.