1.Name: sucker rod couplings 2.Grade: T 3.Attribution: anticorrosion 4.per the customers request to do surface treatment Detailed product description Sucker rod coupling is one of our flagship products. One sucker rod coupling must be processed by a few fabrication procedures, such as, Blanking, drilling hole, boring hole, milling, thread tapping, and so on. At the last step, do the surface ...