These 27 pane windows are used for industrial buildings, engine houses and roundhouses. Each window consists of a 9 pane sash mounted over a 9/9 double hung window. The prototype window would measure 34 inches x 114 inches and has an O scaled opening of .75 inches wide x 2.31 inches. high. Includes 8 windows with pre-cut glazing. Injection molded in gray styrene.