The theoretical wind-momentum-luminosity relation computed for solar metallicity stars (filled symbols) and one-fifth solar metallicity stars (open symbols). The solid line is a linear fit to the calculated wind momentum rates for the solar metallicity stars. The dashed line is the same relation scaled by (Z/Z_⊙)^1/2 with Z/Z_⊙ = 0.2, and is in excellent agreement with the actual computed wind momentum rates at one-fifth solar metallicity (open symbols). For the dotted line we have scaled the wind momenta according to the relations predicted by Vink et al. (2001), i.e., Ṁv_∞ ~ (Z/Z_⊙)^{m + pq + q} = (Z/Z_⊙)^0.82 with m = 0.85, p =  −1.226, and q = 0.13.