Chair with aluminum fixed trestle base on self-braking castors (color matching base). Seat with built-in self-tensioning weight response mechanism, backrest with 3-position recline, adjustable lumbar support breathing up to 2/3". Low backrest with visible backshell (available in black or white), front in polyester mesh in matching color. Seat upholstered in leather, customer's leather, coated fabric, fabric or customer's fabric. Fixed or 2D adjustable armrests in nylon fiber, color matching backshell, are available upon request and with a surcharge.