... listNameSizeGradeCharactersRemarksSucker Rod Coupling5/8”; 3/4”;7/8”; 1”, 1-1/8”T, SM Including the following SM Coupling, ... Coupling5/8”; 3/4”;7/8”; 1”1-1/8”SM It is processed with some special technology, sprayed with ... 3/4”;3/4”-7/8”;7/8”-1”1”-1-1/8”T, SM Connecting two sizes of sucker ... proof,corrosion resisting and reducing the friction, and its lifetime is also longer,even twice of Class T coupling ...