Material alum alloy 6061-t4 or -t6 iaw qq-a-250/11 (sm1870-26 or sm1870-27); finish chromate chemical film iaw mil-c-5541, cl 1a and paint iaw sd1037-05-36 (fed-std-595, color no. 38038); charachters marked iaw sb1198-72-08 outside and iaw sb1198-73-08 inside; dimensions in inches- width 7.560 to 7.580, length 8.750 to 8.770