Stokes number of particles in the fragmentation (blue), bouncing (black) and radial drift (red) limit in 1 Myr old disks around hosts of solar-mass (upper), 0.1 M_⊙ (middle) and 0.01 M_⊙ (lower). The size of the particles is limited by bouncing in disks around solar-mass stars. As masses of central hosts decrease, the radial drift becomes more significant in the outer disk regions.