Best Computer Chair.
A great computer chair, has lasted almost 20 years only the hydraulic cylinder was replaced. I outgrew how high the arm rests go, it collects dust inside the seat so I had made an incision near the front used to clean it out a garden hose once a year would work too. has mesh bottom so it is easier on the back and never makes hard spots on the ass.
If you still have back issues put a soft towel folded in half on the seat part. great for those 12-16 hour days when your still young or 10ish hours for old people.
Update the backrest was the next peice to break, I used some 3d printed tslot and threadrod to fix it while I wait on a new one.