Edge-on FP for the full WINGS sample of ∼1600 ETGs (black open circles), Illustris-1 (red filled circles) and TNG-100 (blue filled circles) at z = 0. The four panels show the distribution of the galaxies in the FP when different range of mass are considered: M_s ≥ 10⁷ M_⊙ (upper left panel), M_s ≥ 10⁸ M_⊙ (upper right panel), M_s ≥ 10⁹ M_⊙ (lower left panel) and M_s ≥ 10¹⁰ M_⊙ (lower right panel). The full black solid line is the best fit of the galaxies of the whole WINGS sample (no lower mass limit). The dashed line is the one-to-one correlation.