When evaluating Fiber Chairs, the shell composition is paramount. High-quality versions typically use a bio-composite material consisting of polypropylene (PP) reinforced with up to 25% wood fibers. This blend provides a unique matte texture and enhanced structural rigidity. Ensure the wood fibers are FSC-certified to meet sustainability standards. For the base, options usually include powder-coated steel, die-cast aluminum, or solid oak/ash wood; verify that metal bases have a wall thickness of at least 2.0mm to prevent bending under heavy commercial use.