High-performance task chair offers large seat and back cushions for support. Functions include back-height adjustment, pneumatic seat-height adjustment from 15-1/2" to 20-1/2", 360-degree swivel, tilt, tilt tension and asynchronous control. Five-star base is made of 16-gauge formed steel with a plastic base cap and has 2" hooded, dual-wheel casters. Seat size is 20" wide x 18" deep. Usable seat depth ranges from 15" to 18". Back measures 18" wide x 18-1/2" high. Arms (height and width adjustable) for chairs are sold separately. Task chair meets or exceeds applicable ANSI/BIFMA standards. Certified by SCS to be in compliance with specific indoor air-quality emission requirements.