Top panel: rest frame NGC 4151 low-resolution spectrum taken with IRTF/SpeX on 2020 May 19. Middle panel: spectrum taken with IRTF/SpeX on 2021 February 1. Bottom panel: spectrum taken with TNG/NICS on 2022 June 15. In all panels, the best fit to the continuum emission (solid red line) is shown superimposed to the data (solid black line) along with the host-galaxy template spectrum (dotted blue line), the AGN power law (short-dashed green line) and the two BB components (long-short-dashed magenta line and dot-dashed yellow line). The major IR emission lines (Landt et al. 2008) are labelled. As per the high-resolution spectra, the different flux levels are due to the lack of an inter-calibration procedure.