Standard solid plastic jumbo arm work surface for extra comfort. MODEL SHAPE HEIGHT DESK J457 A 17.5'' 17.75''x24.5''x31'' J407 - NBRK A 17.5'' 17.75''x24.5''x31''OPTIONSLaminate Work SurfacePermaTuff EdgeBlack EdgePlywood Core Work SurfaceNon-Skid GlidesQ-Ball GlidesSteel Glides