Left-hand panel: colour-magnitude diagram of NGC6749 in a combination of the F606W and F814W. The red square is the position of the counterpart to NGC6749A. The purple curve is a 13-Gyr isochrone calculated at the cluster metallicity, distance, and extinction. Right-hand panel: same as the left-hand panel, but zoomed in on the companion CMD position. The coloured curves are He WD cooling tracks from Istrate et al. (2014, 2016). The tracks are for WDs with masses in the range between 0.17M_⊙ and 0.2M_⊙, with decreasing masses from left to right, as reported in the legend. Different points are also highlighted with different markers along the tracks that correspond to different cooling ages.