Observed and best fit SED of B243 and B331. For each star, the scatter points indicate the dereddened observed photometry and the black dashed lines the Kurucz model used as input for the stellar spectrum in PRODIMO. The best fitting models are drawn in green, with the shaded region indicating the 1σ uncertainty. For B331 the photometry from Lim et al. (2020) is indicated as upper limits; these are not considered in the fitting procedure.