User-friendly gas spring seat height adjustment with intuitive single lever operation. The ergonomically shaped seat and backrest feature synchronous technology with infinitely variable weight adjustment. The seat is adjustable in inclination, height, and depth, while the height-adjustable backrest can be fixed in three positions in the inclination. It includes lumbar support without lumbar adjustment. The five-legged base is made of sturdy tubular steel, is tilt- and trip-proof, and has abrasion-resistant plastic floor glides along with a height-adjustable foot ring for an elevated sitting position. Further technical features include a handle color of blue.