Al aly 6061-t6 qq-a-250/11; chemical treat mil-c-5541 cl1a; 5.000 in. Center of 1st hole to center of last hole; 2.480 in. Center of 2nd hole to center of 3rd hole; 0.58 in. From center of 3rd hole to edge; 0.190 in. Thk; 0.112-40 unc-2b by 0.250 deep 3 holes