Product Description: QEST Fresh Water Piping Fitting, Test Plug IMPORTANT: Flare nuts for both 3/8" O.D. and 1/2" O.D. tubing have 1/2" standard pipe threads and fit 1/2" thread size fittings.
Flare nuts for 5/8"O.D. tubing have 3/4" standard pipe threads and fit 3/4" thread size fittings. ALT Part Numbers: BLP 79SCTP3, 31-5473