Genuine OEM Volkswagen Vented Brake Disc, part number 1EA615301B. This component rotates with the wheel and is gripped by the brake pads to slow down or stop the vehicle. It is positioned as part 1 in the diagram. The vented design helps dissipate heat generated during braking. Genuine OEM brake discs are manufactured to precise tolerances for optimal performance, durability, and heat management, ensuring reliable stopping power.