1. API 11B standard 2.Material: 4120,4142,4330,4720,4620 3. Sinter bar,polished rod ... : Our Sucker rod produced according to API 11B specification.The material is in Grade C, D, K, KD,H,I, HL ... 1/8"φ28.5857.21-9/16" Specification of the material. GradeTensile StrengthYield Coefficient of elongation 200mmSection ShrinkageΨ(%)AKVσb(MPa ...