Evolution of the NS spins (P_spin) versus the orbital periods (P_orb) in converging binaries for β = 0.0 (top), β = 0.3 (middle), and β = 0.7 (bottom). We distinguish the binaries if the final NS mass was above 2.5 M_⊙ (faint gray curves) or below it, which are further grouped by two initial NS masses ($M_{\mathrm{NS}}^i$) 1.3 M_⊙ (blue curves) and 2.0 M_⊙ (orange curves). We also compare to the observed spins of BWs and RBs, shown by the black and red circles, respectively.