Pony rods are used to adjust the length of sucker rod string in oil well. manufacturing specification is API 11B, the specification include 5/8”, 3/4”, 7/8”, 1”, 1-1/8”, the length has 2ft, 4ft, 6ft, 8ft, 10ft, 12ft, our company’s pony rod is Grade D. the material is AISI 4130.