Cookson rolling grilles are an example of CooksonХs uncompromised commitment to quality and value because they have been manufactured with the same proven materials and designs for decades. The grille curtains are still made of 5/16" solid aluminum rods rather than hollow rods and the links are still 1/8" or 3/16" thick aluminum shapes rather than thinner gauge materials. The aluminum extruded guides and bottom bars are still made of heavy-walled shapes.