The CS seal is designed to be used on non-machined, rough surfaces such as that found on the O.D. of oilfield casing. They utilize continuously coiled springs that are scaled to the specific sealing requirement and then integrally bonded to the elastomer during the molding process. These seals are capable of providing a seal across a larger range of tolerances and extrusion gaps than the S seal. CS seals are available for all API 5CT casing sizes.