ISO 2974:2018 specifies the dimensional requirements of end-connections for high-pressure fuel injection equipment components, used on diesel (compression-ignition) engines.

ISO 2974:2018 is applicable to externally threaded 60° female cones (see Figures 1, 2, 5, and 6) and intended for use with high-pressure fuel injection pipe assemblies with tube outside diameters of:

- up to and including 12 mm for integral female cones (see Table 1); and

- up to and including 9 mm for fabricated female cones (see Table 2).

Details of the pipe connection ends referenced in this document are shown in ISO 13296.