See Product Details below... Lumbar and curved back design for optimum support Multi-ergonomic control gives you maximum back pitch adjustment for the pitch and tilt of the seat Pneumatic seat-height adjustment from 17-22" Back-height and tilt-tension adjustment, and tilt-lock Forward tilt control provides separate 0-3° forward tilt Height- and width-adjustable urethane armrests 5-star plastic base with twin-wheel casters Seat: 20Wx18"D; Back: 23-1/2HX20"W Manufacturer's lifetime limited warranty Assembly required