Steel, qq-s-637 comp. 1116 through 1145, cadmium plated finish, qq-p-416 type 2 class 3, 1.240 in. Fastener lg, 5/8-18 unf thd size, 2a thd class, 0.640 in. Lg thd located under head, additional 1/4-18 npt pipe thd 0.600 in. Lg located on end of bolt