The Bertoia side chair is a steel chair here in the fully upholstered version. The frame is a welded steel construction.The side chair frame is available in chrome or satin steel, and black or white Rilsan finishing.The upholstery is in a wide range of materials.This product is available with foam that meets requirements for BS5852.The Knoll logo is stamped into the base of the chair.Harry Bertoia's delicately industrial Side Chair is among the most recognised achievements of mid-century modern design. Like Saarinen and Mies, Bertoia found sublime grace in an industrial material, elevating it beyond its normal utility into a work of art.