Total stellar mass, mass of the (He+CO) core, and mass of the CO core (squares, circles, and diamonds respectively) at the end of HB for the 0.75 M_⊙ models at the different metallicities (colour-coded) as a function of ΔY_ini. Full and open symbols correspond respectively to the models that do or do not reach the TP-AGB phase (and undergo at least two thermal pulses) after central helium burning.