Grade C sucker rod: Moderate strength, not susceptible to sulfide stress cracking; Suitable in sour medium.

Grade D sucker rod: Made of high quality heat treated steel alloy, with high tensile and yield strength; Suitable for non-corroding or mildly corroding environment.

Grade K, KD sucker rod: With good corrosion resistance in H2S, CO2 and NaCl medium, superior tensile strength.

Grade HL and HY sucker rod: High strength; Structure and size matching with grade D sucker rod; Withstanding 966-1, 136 MPa (140, 000-164, 720 psi); Suitable for deep and large displacement wells