Swiss Stop Catalyst 6-hole disc, powerful braking and long life, available in 4 sizes depending on the discipline, racing bike, cyclocross, cross country, downhill and e-bike. The external profile of Catalyst disks does not contain any 90 degree edges. Small hemispherical concavities on the surface show when it's time to replace the disc, when these cavities are flush with the rest of the braking surface, it's time to replace the disc. Optimal heat dissipation. Reliability from cyclocross to downhill. Long service life even in the most extreme conditions.