Comparison of the material ejected by the 25s7B source star model (solid patterns) with the chemical composition of four apparently single CEMP-s stars (Hansen et al. 2016). The ejecta of the source star is made of wind plus supernova with a mass cut set at the bottom of the He-shell. The dilution factor D = M_ISM/M_ej is indicated. The red band at Z = 8 shows the range of [O/Fe] ratios predicted by the AGB models of Karakas (2010). These models have 1 <M_ini< 6 M_⊙ and metallicities of Z = 0.004 and Z = 0.0001.