"MATERIAL 0.250 THICK ALUMINUM, 6061-T6 ASTMB209; 0.190 THICK ALUMINUM, 6061-T6 ASTM B209; 6.00 X 2.50 X 0.170THICK ALUMINUM ASSOCIATION CHANNEL ASTM B308; 4.00 X 2.25 X 0.190 THICK ALUMINUM CHANNEL ASTM B308; 1.00 X 0.375 THICK ACETAL EXTRUSION, GROUP II, CLASS 2, ASTM D4181; FINISH CHEMICAL FILM PER MIL-C-5541, CLASS 1A"