Left panel: cluster mass associated with a 50%, 80%, or 95% detection probability (from bottom to top), for the XXL selection function C1, as a function of redshift. Middle panel: minimum detectable cluster mass, as a function of redshift, for the Planck space mission. Right panel: cluster mass associated with a 50%, 80%, or 95% detection probability (from bottom to top), for the Erosita selection function as a function of redshift (we consider a flux limit of 4 × 10^-14 erg   s^-1   cm^-2 in the  [0.5 − 2]  keV band).