Top: ${\mathcal{M}}_{\mathrm{e}}$ vs. BSS age (found with isochrone models) for OCs. Middle: ${\mathcal{M}}_{\mathrm{e}}$ vs. BSS age (found with isochrone models) for GCs. In both Top and Middle panels, the dashed gray lines used to separate the BSSs classified as “upper” or “lower” sequences. OC BSSs and GC BSS that are tagged as “upper” sequence BSSs are symbolized by blue triangles and yellow squares, respectively. “lower” sequence for OCs and GCs are represented by green plus (+) symbols and red dots, respectively. Bottom: CMD (using absolute magnitudes and de-reddened colors) based on BSSs sequence tag. Symbols are the same as the top figure.