Task chair features large seat and back cushions for comfortable support while seated and an easy-to-adjust back height adjustment. Other functions include pneumatic seat-height adjustment from 17" to 22-1/2" high from the floor and 360-degree swivel. Arms (height and width adjustable) for chairs are sold separately. Molded, polymer outer back shell is color-coordinated with the base. All nonupholstered parts are color-matched. Five-star base with casters is designed for stability. Seat size is20" wide x 18" deep. Back measures 18" wide x 18-1/2" high. Usable seat depth is 18".