The hand-operated, air lift Ritter 128 features a chrome five-caster, star-shaped base allowing physicians to get in close during exams. A surgical armrest (backrest) stabilizes the surgeon's arm during delicate procedures. The thick, but firm, foam padding enhances comfort, while the dual hooded silent casters allow the physician to sit on the edge of the seat roll around the room and never tip. The stool height adjusts from 16-1/2" to 24-1/2".