As this model is not documeted in any of the Knoll catalogues, the cabinet was probably a special order.
Birch, maple, plastic and leather
24 1/4 x 60 x 24 in. (62.2 x 152.4 x 61 cm)
Steven and Linda Rouland, Knoll Furniture 1938-1960, Atglen, PA, 1999, p. 144 (for a telephone cabinet of related form)