API sucker rod coupling, class SM

It is made of good quality steel alloy 40 Cr and processed with some special technology, coated a layer of abrasion-proof, wear-proof and lessening friction coat. With the API standard and also ISO standard, it can not only protect itself but also the rod, preventing and slowing down the wear. It is available in 5/8, 3/4, 7/8, 1, 1 1/8 with full size and slim hole.
1) Material: Seamless Alloy Steel 40Cr (AISI 5140)
2) Standard: API Spec 11B
3) Class: T& SM
4) Main specification: 5/8", 3/4", 7/8", 1", 1 1/8"
API sucker rod coupling, class SM