Professional chair features built-in lumbar support – arms that adjust in height and width and a VeraFlex breathable fabric back with matching VeraFlex fabric seat. Functions include one-touch pneumatic seat-height adjustment – synchronized knee tilt and integral lumbar. Heavy-duty nylon – five-star base has oversized dual-wheel casters. Seat size is 19-1/2″ wide x 20″ deep x 4″ high. Back measures 20″ wide x 19″ high. Distance between arms is 18-1/4″.