Mean effective radius and Sérsic index as a function of spectroscopic velocity dispersion (left, black filled diamonds), model velocity dispersion (left, black open triangles), and stellar mass (right, black diamonds). In red, we show the averages for the lens samples that simultaneously satisfy 180 km s^-1 < σ_mod < 300 km s^-1, 180 km s^-1 < σ_spec < 300 km s^-1, δσ_spec/σ_spec < 0.15 and 10.8  .