JLP billet water bypass fittings increase engine performance by diverting some of the water from the cylinder head to the bypass fitting, rather than forcing all of the water through the exhaust system. This machined bypass fittings is angled at 90 degrees of flow. Fits 3/8" ID Cooling Hoses. Hose Diameter: 3/8" Inch Nut Width: 11/16" Inch NOTE: Install with 1/2" Inch Drill Bit. COLOR: Purple