Matl aluminum, qq-a-250/8, 5052, h32; finish chem film, mil-c-5541, type ii, grade c, class 3; 4.438 in. O/a lg, 3.438 in. O/a w, 0.438 in. O/a thk; four 0.187 in. Diameter holes located 0.218 in. From each corner thru; six 0.096 in. Diameter holes through with counterbore to 0.175 in. Diameter irregularly spaced; two 0.125 in. Diameter holes irregularly spaced