Pro-Flex’s offering includes a traditional yellow jacket version (Pro-Flex 1) and a black jacket arc-resistant version (Flak Jacket). Both versions can be used with either natural gas or LP and utilize the same dual-seal, gasket and O-ring connection system that virtually eliminates the problem of leaks due to “bad cuts.” Pro-Flex CSST is a 21 year-old Indiana based company that was acquired by the ownership of Sioux Chief Mfg. in 2014. The company provides flexible tubing, fittings and accessories for use in gas line installations.