Safco Master High-Back Economy Industrial Workbench Swivel Task Chair, Black (5117)

Expensive, but worth it. We use these stools in a shop environment and we have not had a stool perform this well in our 20 plus years of business. The bottom does sit outside the seat a bit, so we do trip on it from time to time, but after few weeks, we have adapted to the design.

My butt does get numb, but it's a great sturdy chair!