DBA's 4000 Series and 5000 Series rotors can be further enhanced with optional slots known as T3 - 48 CNC machined tri-directional curved slots. Machined slots in the friction surface allow a channel for braking by-products - brake dust and gasses from the incredible heat - to escape. This has a multitude of benefits, from reducing pad contamination, controlling heat build-up, and brake pad knock back. These combine to enhance braking performance and increase service life of the pads and rotors. Compared to more common straight slots, the unique curved slot design reduces the noise associated with 'racing' brakes, and minimises any detriment to pad surface condition.