These Premo drafting height 24" to 29" chairs ergonomic features & rugged contemporary design make for reasonably priced seating comfort. The chairs have orthopedic spine support backrests and full-size upholstered contoured seats for comfort. They features pneumatic height control, polypropylene seat and back shells, a height- and depth-adjustable backrest with heavy-duty spring tension angle control, dual-wheel casters, and a 25" diameter reinforced nylon base. Their seat cushions are 19"w x 17"d x 3" thick. Backrest is 16"w x 14"h x 2½" thick.