Reconstructed HE mass (M_HE) obtained assuming spherical symmetry. Top panel: total mass (M_tot, black curve), M_HE median (green) and M_HE mean (blue). Bottom panel: relative residuals: the hydrostatic bias (computed as (M_tot(r)−M_HEmedian(r))/M_tot(r)), is shown in black; and the effect of substructures ((M_HEmedian(r)−M_HEmean(r))/M_HEmedian(r)), in cyan. The vertical lines represent R₅₀₀ and R₂₀₀: (a) for the relaxed cluster CL135; (b) for the dynamically active cluster CL77.