MESA-derived inverses of density mean concentration factors for MS stars of a range of masses (0.1, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, and 20.0 in units of M_⊙) and two metallicities – 0.02 and 0.002. The shaded regions illustrate the variation in over the MS lifetime, with a TAMS star having the lowest value and a ZAMS star having the highest (the values are for ZAMS stars only in the cases of stars of masses < 1 M_⊙). The two dashed horizontal lines represent the corresponding values for polytropic stars, shown in Table 3.