DIFF Subgroup
F03G 7/063 Full Title
Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for > using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like (using thermal expansion of non-vaporising liquids F01K)
Of 6 combined children, 0 exist in both systems.
6 codes are CPC-only extensions.