Prescriptions for mass dependence of wind braking law, f_M*, considered in our models. The range of variability due to stellar evolution in the age range spanned by our models (≈0.1 − 4 Gyr) is also shown. The increase in the variability width at the two ends of the mass range is due to the prolonged pre-main sequence phase, and to the earlier onset of the post-main sequence phase, respectively, in comparison with the stars in the middle of the mass range.