... sucker rod coupling line, claa T, SM, UUS, including sucker rod coupling, subcoupling, polished rod coupling,CROSS OVER coupling. Spraying Metal coupling combines top quality steel ... Coupling, class SM, for Connecting two sizes of sucker rod 1)Material: seamless alloy steel 2)Standard: API Spec 11B 3)Grade SM ... a longterm business relationship with you. cross cover sucker rod coupling, api 11b coupling