The chair is swivelable and offers ergonomic seating comfort. Base: This variant features a metal Aluminum swivel ring base, which is typical of the vintage models from the 500 series. Design by Geoffrey D. Harcourt for Artifort. Comes with its original Orange Flower upholstery. Slight discoloration on the base. Early example. Status: The F504 is a sought-after collector's item. I have official proof of authenticity such as vintage catalogs, designer records, or other literature sources and take full responsibility for any authenticity issues arising from misattribution