These thread sealants are a variation of our basic RectorSeal® No. 5® formulation modified for specific applications where low odor, non-staining and soft set features are desired. RectorSeal® No. 5® Special is especially formulated for use around gas detection equipment. RectorSeal® No. 5® Sub-Zero is especially formulated for low temperature applications and is brushable to -35 deg F. They are listed under the Uniform Plumbing Code (IAPMO) File No. 1282. In addition, they are approved and listed with the Canadian Standards Association (CSA).