Example of injection of mock radio halos in PSZ2 G126.28+65.62. Left: original image. Middle: injected radio halo with a flux density of 1.0 mJy. Right: injected radio halo with a flux density of 1.5 mJy. Radio contours are displayed starting from the 2σ_rms level. The two circles display the R₅₀₀ area, with the white one centred on the cluster (see cross) and the yellow one centred on the injected halo.