Comparison of the T2CEP models with the T2CEPs in our sample. The triangles represent stars pulsating in the first overtone (based on the Gaia classification), and the dots represent the stars pulsating in the fundamental mode. Anomalous Cepheids are marked with the symbol ×. The dotted lines are used to indicate the boundaries of the IS as defined by the models. The best-fitting models for the majority of Cepheids are shown in red, whereas those fitting the least are in turquoise. The percentage of stars within the boundaries of each model is given in Table A.3.