Office chair with pneumatic gas lift for height adjustment and 360 degree swivel Primary Material: Ergonomic Co Polymer chair with black contoured meshback, Strong Plastic Armrest, Heavy Duty Plastic Umbrella Shape Base, Pneumatic 5-inch-seat height adjustment & 2-inch-thick padded seat for day long comfort. Color: Black with certain silver colored parts. Revolving office chair with many adjustable features like tension control etc.