CARMENES spectra of GJ 180 (M1.0, top panel), Ross 128 (M4.0, middle panel), HD 180617 (M8.0, bottom panel) in black is compared with the best-fit BT-Settl model (red). The main spectral features which includes atomic lines such as Fe I, Ca I, Na I, K I, Si I, Mg I, Al II, along with some hydride bands such as those of FeH and OH can be seen. We used mainly Tinney & Reid (1998), Reiners et al. (2018) for the spectral features recognition and labeling. Their best value of T_eff, [M/H] and log g is given in Table 2.