Comparison of the photometric evolution of ZTF 18aaqeasu with that of the He shell double detonation models in Kromer et al. (2010; K10, dashed lines) and Polin et al. (2019; P18, solid lines). The model parameters are indicated in the legend as (WD mass, shell mass, mixing length), and where NM stands for No Mixing. The left panel shows the r-band evolution, while the right panels show the g − r and r − i color evolution with the same color schemes for the models. On the right panel, circles denote colors derived from the spectra, while squares denote colors derived from photometry.