Upper left panel: The rest frame wavelength of the reference band (in our work always the g-band), λ_ref, versus the rest frame wavelength of the secondary light curves, λ_S, used to measure the time lags. Upper right panel: The M_BH as a function of λ_S for the objects in our final sample. Bottom panels: Same as the top right panel but for λ_Edd and L_{2 − 10 keV} (left and right panels, respectively). The boxes in all panels indicate the measurements we used to compute the mean time-lags spectrum.