Remnant mass function of single stars depending on their initial mass. The colour and symbol show different metallicities. We used the direct collapse prescription in POSYDON. At Z ≤ 0.2 Z_⊙ stars with initial masses above 100 M_⊙ might not form a BH because of pair instability and are shown here with a zero mass. Stars with initial masses above the pair-instability gap form BHs outside the plotted range, with masses above 100 M_⊙ at the lowest shown metallicity.