sucker rod coupling, rod joint, API 11b coupling class ... SM, T, UUS, full size&slime hole 45000pcs/month, special manufacturer We produce the whole API sucker rod ... coupling line, claa T, SM, UUS, including sucker rod coupling, subcoupling, polished rod coupling,CROSS ... class SM, for Connecting two sizes of sucker rod 1)Material: seamless alloy steel 2) ...