several types of parallel thread port studs DIN Metric flat face (ISO 9974); BSPP flat face (ISO 1179); SAE straight threads (SAE J1926 / ISO 11926); ISO (ISO 6149); JIS (JIS B2351).●?DIN Fittings with tapered thread port studs: NPT thread ANSI/ASME B 1.20.1-1983; BSPT thread ISO 7/BS 21/DIN 2999-1; Metric thread metric DIN 3852-1, Inch thread DIN 3852-2.