Montage of the synthetic optical spectra of massive stars at the pre-SN stage from non-rotating stellar evolution models. Observations of stars with similar spectral type (dashed) are shown to support the spectroscopic classifications. The strongest spectral features are indicated. The spectra have been offset in flux for better visualization. a) The 25 M_⊙ model (black), which has a WN11h/LBV spectral type. The 1989 June observations of the LBV AG Car (red) are also shown, when it showed a WN11h spectral type Smith et al. (1994); Stahl et al. (2001); Groh et al. (2009b). b) The 32 M_⊙ (red) and 40 M_⊙ (black) models, which have spectral type WN7–8o, are compared to observations of Galactic WN7o (WR120) and WN8o (WR123) stars, form the catalog of Hamann et al. (1995). c) The 50 M_⊙ (cyan), 60 M_⊙ (blue), 85 M_⊙ (red), and 120 M_⊙ (black) models, which have WO1–3 spectral type. The spectrum of the 60 M_⊙ model with Ṁ enhanced by a factor of two at the pre-SN stage is shown (orange dot-dashed). The optical spectrum of the Galactic WO 3 star WR 93b (green, from Drew et al. 2004) is also displayed.