This special yellow pipe tape should be used on all threaded joints and fittings in your propane gas system. Unlike the more common white pipe tape used by plumbers for water fittings, this tape is especially manufactured thicker and denser for assemblies handling natural gas, butane and propane. Use it with your regulators and throughout your system. The only location it is not needed is with flare fittings and with the newer Acme Type 1 green plastic hand-tighten fittings that attach your pigtails to the tanks. It is absolutely needed for your pigtails where they attach to the regulator and for the regulator where it attaches to the main line to the trailer. Each spool is 1/2" wide and 260" long.