Big and Tall Double AirGrid® Back and Mesh Seat Ergonomic Chair with Built-in Adjustable Lumbar Support. Thick Padded Black Mesh Seat and Double AirGrid® Back with Built-in Adjustable Lumbar Support. One Touch Pneumatic Seat Height Adjustment. Mid Pivot Knee Tilt Control. Adjustable Tilt Tension Control. Height and Width Adjustable Arms with PU Pads. Big and Tall to 400lbs. Extra Heavy Duty Gunmetal Finish Base with Oversized Dual Wheel Carpet Casters.