Mass-loss rates (upper panel) and wind velocities (lower panel) for all DARWIN models with a stellar wind, and for three observational sets (SRVs, Miras, and OH/IR stars). The wind properties for SRVs and Mira variables are from Olofsson et al. (2002) and González Delgado et al. (2003) and the wind properties for the OH/IR stars are from De Beck et al. (2010) and He & Chen (2001). All the observed wind properties are estimated from CO-line emission, except for the sample from He & Chen (2001), where the mass-loss rates are estimated from dust emission.