NTT/SofI spectrum of 2MASS J0249−0557 c (black) compared to old field L standards from Kirkpatrick et al. (1999, 2000) observed with IRTF/SpeX (coloured) by Burgasser et al. (2004, 2010), and Cruz et al. (2018). The NTT/SofI spectrum was convolved with a Gaussian to match the resolution of SpeX spectra. J, H, and K bands are displayed and normalised separately. Some spectral features, such as the VO, FeH, H₂ O, and CO bands or the NaI and KI doublets, are marked in grey.