Extra large, ergonomic, comfortable seat & backrest: contoured cushion is fully padded by high-density soft sponge for all day comfort. Supportive back helps you relieve fatigue of your back. Sit relaxedly in a thoughtfully designed chair that adjusts height & tilt according to your needs. Height adjustable & Easy operation: Equipped with a tall & smooth lifting gas lift cylinder, adjustments are easily controlled with hand lever, seat height range from 19.7 inches to 27.6 inches to meet users of varying heights and applications. Safety security: The heavy duty stool is well constructed, very sturdy and durable. Made by top quality materials - heavy duty aluminum base in solid structure measuring 25.2 inches provides extra stability, nylon twin-wheel casters and gas lift cylinder meet ANSI/BIFMA X5.1 & EN 1335 General-Purpose Office Chairs quality standard with SGS testing and certification.