Crossbars add rigidity and strength to large size screens. Crossbars are almost always installed across the mid-point of the screens longest side. Crossbar frame is a box type frame that is 3/4" x 5/16" and made of roll form aluminum. Use crossbar clips to attach the the sides of the screens. This crossbar is a unpainted silver finish. Full box is 168 sticks at 12" 6" length.