Spectral disentangling procedure applied to 66 Eri. Dots show the observations and the solid line is the model spectrum for corresponding phase. Black solid lines at the bottom represent disentangled spectra for the primary and secondary components. The lines above the continuum level represent the standard deviations in the reference frames of components A and B. Peaks at the location of spectral lines in the standard deviation indicate the presence of intrinsic variability in a given line (Y ii 4358.728 Å, Ti ii 4367.652 Å, and Y ii 4374.935 Å in this spectral interval).