The spectrum of VFTS 527 (O6.5 Iafc + O6 Iaf) shows the characteristic of a SB2. The temperature and mass-loss rate are difficult to determine. We tried to fit the spectrum with a single model from our grid. The line width of the absorption lines suggests a lower log g. The fit quality is poor as result of the SB2 characteristic and the derived T_eff, Ṁ and the luminosity are quite uncertain. No He enrichment at the stellar surface. Combining two single star models would improve the fit quality.