Painted & Drilled & Slotted Brake Disc

Painted brake disc, drilled and slotted

As brake rotors are made of iron, they naturally rust and when exposed to minerals such as salt, the rusting (oxidization) tends to speed up. This leaves you with a very ugly looking rotor.
Naturally, companies started looking at ways to mitigate rusting of the rotors. One way was to get brake disc pained to prevent rust.
Also for higher performance, please will like the drilled and slotted style rotors.

Why do drilled or slotted discs improve braking
The presence of holes or slots on a brake disc is a guarantee of better grip and certainly a more responsive and effective braking system. This effect is due to the surface of the holes or slots which ensure, especially in the initial braking phases, better performance thanks to a higher friction coefficient than that of standard discs.

Another important advantage to using drilled and slotted discs is the constant renewal of the pad friction material. The holes also interrupt the sheet of water that can deposit on the braking surface in the rain. For this reason, even in the case of wet roads, the system responds efficiently from the very first braking operation. In the same way, the slots, which face outward, ensure more effective dispersion of any water that may be on the disc surface: the result is more uniform behavior in any weather conditions.

When they reach high temperatures, these gases created by the combustion of the resins that make up the friction material, can cause the phenomenon of fading, which reduces the friction coefficient between disc and pad, with a consequent loss of braking efficiency. The presence of holes or slots on the braking surface allows for rapid expulsion of these gases, quickly restoring optimum braking conditions.