2material aluminum alloy ams 4261, alternate: aluminum alloy 6061 per qq-a-250/11 t4 or t6; finish lacquer per tt-l-50, optional type, color no. 37028 federal standard 595, alternate: optical black paint per mil-p-47160; 0.607 in. Lg; 0.350 w; 0.275 in. Deep