Notes. The second column lists the mass-loss rate value derived in recent optical studies using atmosphere models: [1]: Crowther et al. (2006), [2]: Searle et al. (2008), [3]: Hamann et al. (priv. comm.; Fossati et al. 2015), [4]: Najarro et al. (1996). The third and fourth columns provide the mass-loss estimates from the formulae of Vink et al. (2001) when the adopted T_eff is in the range 12 500−22 500 K (cool side of the bi-stability jump) and 27 500−50 000 K (hot side of the bi-stability jump), respectively. When the adopted T_eff (Table A.1) is in the range 22 500−27 500 K (in the bi-stability jump), mass-loss estimates for both the cool and hot sides of the bi-stability jump are provided. The fifth column yields the total X-ray emission measures, estimated from the normalisation factors of the spectral fittings (Table 1). The last two columns provide the mass-loss rates predicted by Eq. (1) of Huenemoerder et al. (2012, with b = 0.97 and the formula on p. 1868 of Cohen et al. (2008), respectively. In these columns only a range of mass-loss rates are given: the lower values correspond to a terminal wind velocity of 500 km s^-1, while the highest values correspond to a terminal wind velocity of 1500 km s^-1.