Are these taper thread fittings - NPT or NPTF? In a message dated 07/06/2008 20:49:37 GMT Daylight Time, tncarnut1 at yahoo.com writes: This adjustable regulator has three different sizes of fittings (for use with different fuel line diameters) that screw into the regulator on either side. What should I use to seal the fittings?