Energy-resolved pulse profiles of RX J0440.9+4431 obtained by folding the light curves from Insight-HXMT LE (1–10 keV) (two panels from left), ME (10–30 keV) (two panels in the middle) and HE (30–150 keV) (two panels from right) light curves at a similar luminosity during the progress and decline of the giant outburst. Two pulses are shown in each panel for clarity. The error bars represent 1σ uncertainties. The epochs of the observations in MJD are shown inside each panel on the left. The corresponding source luminosity estimates in 1–120 keV are shown in the middle of each panel.