This Arm Chair, in the Collection of The Henry Ford, consists of molded fiberglass with dark brown padded hopsak upholstery that has a ten-inch opening between the back and seat. The shell sits on a tilt, swivel four blade metal base on black casters. A chair matching this description cannot be found in any Herman Miller Trade Catalogues. This confirms that it is probably a prototype. However, the base does suggest a date circa 1963.