Steel, black oxide, rockwell c hardness 40 min 44 max, 5.484 in. Min, 5.516 in. Max lg, first end 3/8-24 unf-2a thd, 0.359 in. Max thd lg, second end 0.2370 in. Dia, 16 thd per in. Double thd america standard acme 29 degrees stub thd, 4.705 in. Max thd lg, 0.500 in.Shoulder dia