Density distribution in magnitude-colour (left) and colour-colour space (right) of our synthetic catalogue highlighting potential LISA sources (magenta) with respect to the rest of the remaining systems (blue). The black points are confirmed WD observations, while purple markers are detached DWD VBs. We note that several VBs fall directly in the magenta area when reddening is removed and a more stringent magnitude limit is applied. On the right, the grey lines define the colour cuts used in our analysis.