Mass-loss rates vs. wind velocities from DARWIN models of M-type AGB stars with a stellar wind (indicated in red in Fig. 6) and the corresponding properties from observed M-type AGB stars, derived from CO-lines (Olofsson et al. 2002; González Delgado et al. 2003, black crosses). All panels show the same data but with colour-coding according to stellar luminosity, stellar mass, effective temperature, L_* ∕M_*, seed particle abundance, piston velocity amplitude, grain size, and gas-to-dust mass ratio.