Optical LS-DR10 image (top) and smoothed eROSITA count rate image (bottom) of ACT-CLJ0840.5+0543 (z=0.28, SNR=9.75). This is one of 924 ACT-DR5 MCMF clusters with matches in the eRASS point source catalog. This particular cluster, along with ~70 other clusters in the common eRASS1-ACT-DR5 footprint, is missing from the eRASS1 cluster sample but is included in the RASS-MCMF cluster sample.