CTS manufactures Copper Companion Flanges. The CTS Copper Companion Flange, a fully floating flange, is such a logical development in copper tube installation that it is hard to believe that no one has thought of it before. The concept is very simple. Instead of having to install a brass companion flange that requires careful alignment of bolt holes during brazing, the CTS Copper Companion Flange uses a copper fitting brazed/soldered directly to the copper tube, backed by a fully floating powder coated steel flange fitted with a neoprene insulator. The integral insulator allows the CTS flange to offer 100% protection against electrolysis.