Commander Series Options FABRIC ARMRESTS WHEELS Features Height Adjustable Headrest 2.5" Adjustable Standard Armrest Seat Back Angle Adjustment Tilt Rocker Adjustment Five-Star Base Steel Frame Seat Cushion Tilt Adjuster (7 Degrees - 3 Positions) Seat Cushion Length Adjuster (50 mm) Adjustable Upper & Lower Air Lumbar Gas Lift Height Adjustment Front Tilt Adjustment 2.5" Double Wheel Casters Replacement For KAB Office Chairs K1, K4 Premium, Associate, Iron Horse Office Chairs