Colors (no correction for interstellar reddening) for our sample of carbon stars (filled symbols), using the 2MASS filters. The green symbols indicate the Mira-type stars, while the gray symbols are for the stars outside of the color range of the models. The synthetic colors (open diamonds) of our grid of hydrostatic models are overplotted for comparison. The orange line shows the effect of reddening using a simple extinction law (Cardelli et al. 1989). The bars plotted show the ± 1σ root-mean-square deviation of our photometry with respect to the literature (large-amplitude variables excluded). This is an upper limit of the uncertainties in the flux calibration and any possible residual variability.