High or medium backrest. Tilting mechanism or offset tilting mechanism or swivelling. Central recline adjustment knob , in action with body weight, with anti-shock return. Gas lever for seat height adjustment. Supporting inside shell in beech plywood, flexible polyurethane upholstery, not deformable, fireproof. Chromed steel armrests with upholstered and covered pad armrests. Polished aluminium 5 spokes safety base. Cantilever closed form base, chromed steel rod. Self-braking castors D.65, hard or soft tread.