Aluminum alloy per qq-a-250/11 6061-t6; chemical film surface treatment per mil-c-5541, class 3; 0.190 in. Material thickness; length 1.313 in.; width 1.313 in.; four 0.144 in. Diameter through csk 82 degrees by 0.280 in. Diameter holes on a 0.994 in. By 0.956 in. Mounting center