OptionalreferenceDiameter: numberOptionalmodule: numberOptionalunit: unitOfLengthEnumOptionalreferenceThe diameter the spline is named by, in millimetres as DIN 5480 names it, such as 25 in W 25x1.25x18.
OptionalmoduleThe module of its teeth in millimetres, one of DIN 5480's: 0.5, 0.6, 0.75, 0.8, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 4, 5, 6, 8 or 10.
OptionalunitThe unit the spline's sizes come back in.
A DIN 5480 involute spline's reference diameter and module, and the unit its sizes come back in, for
engineering.mechanical.splines.din.involuteSplineSizes.