The height is ajustable by removing the centre pin and wingnut at the crossover point of the legs and putting it thought a different hole, thus allowing the legs to spread out and lower the seat.
The one leg is fixed under the seat while the other clips in place and allows the seat to be collapsed flat. Four rubber tubed-feet hold the seat on my polished floor, without slipping, and the seat is very well padded. The seat covering is PVC, but of a good quality and does not sweat me. Brought one seat for the Tyros and one to go with my other keyboard I gave to my grandchildren. There is a cheaper seat, but you have to make sure it will take your weight, check before buying.