BEVCO® Ergonomic Chairs Ergonomic Chairs provide total body comfort. Features include pneumatic height adjustment with 360 degree swivel, fully adjustable backrest, five star reinforced plastic base, and waterfall seat design with high-density foam. They have a 12 year "intensive use" guarantee with lifetime cylinder warranty. Seat is 20"W x 18"D x 3" thick and back is 17"W x 18"H x 3" thick. Other fabric and vinyl colors available. Industrail Task Chair has a seat height range of 24"-34" and comes standard with adjustable chrome foot ring. Choose stationary glides or hard floor casters