Office chair with 5 way swivel base on castors (for hard floors, in the same color as the base) in polished or lacquered aluminum, fitted with gas-lift mechanism for height adjustment. Seat with built-in self-tensioning weight response mechanism, medium backrest with 3-position recline, adjustable lumbar support breathing up to 60 mm. The shell is available with front face upholstery backrest in nylon mesh in the same color as the exposed backshell (black or white) and seat upholstered in leather, customer's leather, faux leather, fabric or customer's fabric, with backrest and seat with front face upholstery in leather, customer's leather, faux leather, fabric or customer's fabric or with full upholstery in leather, customer's leather, faux leather, fabric or customer's fabric. Fixed armrests in nylon fiber, color matching with backshell, are available upon request and with a surcharge. Back and seat can be ordered in different colors of the same upholstery, with a surcharge.