Retention fraction of dark remnants as a function of system mass if we assume that the main mechanism of dark remnants ejection are SN kicks with a Maxwell-Boltzman kick velocity distribution shown in Fig. 1. We assumed two different mass-radius relations (red and blue curves, as in Fig. 1), radii for each mass being written next to the corresponding points and a normalization described in the text. In black and grey we plot retention fractions if larger kick velocity dispersions are assumed. In this case we use the mass-radius relation from Marks & Kroupa (2012).