Subsets of MIST age isochrone (Choi et al. 2016) used in our SPISEA (Hosek et al. 2020) stellar population synthesis featuring a range of ages as shown in the legend. The metallicity of each of the subsets is reflected by their line style, as is shown in the bottom legend. None of them have any dust extinction, and the color represents the age of the isochrone, as is shown in the top legend. For each age isochrone, we also annotate some characteristic masses to indicate the mass-age dependency.