... 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 ... )Material: seamless alloy steel 2)Standard: API Spec 11B 3)Grade SM, Fullsize or slimehole4)coupling diameter: 5/8"-3/4",3/4 ... a longterm business relationship with you. cross cover sucker rod coupling, api 11b coupling