T_eff − log g diagram of the sdB binaries with spectroscopic parameters (black squares) compared to the reflection effect candidates (red diamonds). The solid black lines mark the zero-age extreme horizontal branch (ZAEHB), the terminal-age extreme horizontal branch (TAEHB), and the He main sequence (He ZAMS). The dashed lines are evolutionary tracks by Dorman et al. (1993) for sdB masses of 0.471, 0.473, and 0.475 M_⊙. The dotted lines are tracks for extremely low-mass white dwarfs of a mass of 0.27, 0.32, and 0.36 M_⊙ by Althaus et al. (2013).