This is a classic Bertoia Diamond Chair, Model No. 421, originally designed by Harry Bertoia for Knoll in 1952. This particular example dates to the early 2000s and came from a corporate office in NYC. The piece is constructed of a chromed-steel wire seat, which sits atop a sled base of the same material. The chair is fully upholstered, retaining its original seat cover in Knoll “Iris” purple bouclé. The frame is unmarked, though both frame and upholstered pad are guaranteed as authentic Knoll examples. Knoll did not start engraving the frames of the chairs until the mid 2000s. Presumably this fell just before then as far as production timing. This likely had a paper label at one point, which are notorious for falling off as the adhesive weakens.

The chair measures 33.5 inches wide, is 30 inches tall and 28.25 inches deep. The seat height is 16.5 inches. The piece is in excellent condition with only light wear from use. See photos.