Blow molded backrest fits NPS® Elephant Z Stools. Fan back design for greater comfort. • Fan back backrest for greater comfort. • Blow molded polypropylene. • Durable design. • Fits NPS® Series 6600 Elephant Z Stools. Blow molded backrest fits NPS® Elephant Z Stools. Fan back design for greater comfort. Series Name: NPS® 6600 Series Elephant Z; Color(s): Black; Color Family: Black; Material(s): Plastic; Steel.