Flexing back is constructed of ilira® a multidirectional stretch material that provides air flow and breathability. Fabric is soft and non-abrasive so it won"t damage clothing. Height- and width-adjustable arms for a custom fit. Five-star base has casters for easy mobility. Recommended Applications: General Office & Task Seat/Back Color: Black Features & Functions: 360° Swivel Pneumatic Seat Height Adjustment Seat Glide Mechanism Synchronized Knee Tilt Tilt Lock Tilt Tension Arms Included: Yes.Unit of Measure : Each