Dorsal® Chair and Tandem seating options. Time-proven reliability and sturdy construction assure the continued popularity of Dorsal seating. Chairs are available in seat and frame styles that make them appropriate for use in applications from the office to classroom. Highlights: Thermoplastic shell, upholstered seat, or upholstered seat and back; Two frame styles (round leg or oval leg); Arms, armless, or tablet arm; Optional bookrack; Ganging.