The scaling of both the L-H threshold and confinement with the mass M of the hydrogenic isotopes is discussed. The confinement in the core and edge are found to scale differently with M and a two region model is developed to represent the physical behaviour of each region. Identity pulses with the same profiles of the dimensionless physics parameters r*, n* and b are obtained with different isotopes, H and D; this result suggests that there is no explicit mass dependence of the transport in either the core or edge regions.