API Suck rod coupling 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 treatment. The surface treatment includes black coating, phosphating or per the customers' requirments. Besides, it has good anticorrosion and anti-friction property. The following table shows the related information about the sucker rod coupling.