Tube, steel carbon, astm a512, a513, or a519 or steel alloy, astm a513 or a519; cadmium plate, qq-p-416, type 2, cl 3; tube o.D. 0.438 in., wall 0.083 in., lg 19.000 in.; ctr to ctr between end connections 21.625 in.; both ends of tube internally threaded 0.312-24unf-2b, thread lg 1.500 in.