Steel casting, mil-s-867 cl1; passivate qq-p-35, type "as appropriate" subsequent to final machining; 8.125 in. L; 2.125 in. W; 2 holes with 0.1959- 0.2067 diameter thru, 1/4-20 unc-2b-1/2 min. Full thd; steel stamp, etch or engrave "10001-1599645" in 1/4 characters on side