Stackable slide frame in highly resistant tubular steel, Ø 25 x 2 mm, with chrome-plated or white or black lacquer finish and plastic supports. Internal structure of seat in nylon, with underseat casing in polypropylene. Flexible fireproof injected polyurethane padding. Backrest structure in white ABS or in transparent polycarbonate. The version with mesh backrest has a chrome-plated steel rod support. The upholstered backrest has an ABS support with flexible polyurethane padding, upholstered in fabric or leather at the front and at the back. The backrest is joined to the frame with a coupling element in polished pressure die-cast aluminium. Elbow-rest in visible black or white polypropylene or upholstered on request.