Couplings supplied by Jereh include sucker rod coupling, sub- coupling and polished rod coupling. They are designed in accordance with API Spec 11B and are made of fine carbon-steel. Normally, they have two wrench flats on the outside diameter but they also can be provided in no-wrench flat when required by user. Grade T coupling hardness is HRA58~62(HRC16~23) after heat treatment, possessing better anti-corrosion property and abrasion-proof property.

  Sucker rod coupling is used for connecting the same size of sucker rods. Sub- coupling is used for connecting the two sizes of sucker rods or a polished rod to a sucker rod string. Polished rod coupling is used for connecting the polished rod to the sucker rod string.

  Please note, the use of sucker rod coupling on polished rod will result in split coupling.