Yunsheng is the manufacturer offering API sucker rod coupling in Shandong China. All the rod couplings are produced by API 11 B standard. These sucker rod coupling are very cost effective, including class SM sucker rod coupling, class T sucker rod coupling, Sub sucker rod coupling, Full Size coupling, Slim Hole coupling. They are available in 5/8", 3/4", 7/8", 1" and 1-1/8". Manufactured with high quality Carbon steel AISI 5I40 /4135 . If you have any interests on our sucker rod coupling, please feel free to contact us for further information! And we can also provide API sucker rod for you without any extra profit from our brotherhood company.