Circumstellar material in our models at the time of the SN, according to various estimates, versus the SN ejecta mass. The CSM mass given by ΔM_RLOF−BC (white, with black outline) and $\mathrm{\Delta }{M}_{\mathrm{RLOF}-\mathrm{BC}}^{(4)}$ (black) is shown. CSM mass estimates for models in the binary grid are given as smaller white triangles with gray rim, and the region occupied by these models is shaded in gray. The results from the models in WF22 undergoing Case X RLOF are shown as purple dots and distinguished between the case in which mass transfer is assumed to be stable (filled) and unstable (empty). The background colormap represents the estimated maximum conversion fraction of kinetic energy into radiation via CSM interaction (f_M, Eq. (2)).