Genuine OEM Audi brake caliper housing, part number 8K0615123C. This is the primary structural component of the brake caliper assembly. It houses the brake pistons which, when activated by hydraulic pressure, press the brake pads against the brake rotor to slow or stop the vehicle. Constructed from high-strength cast iron to withstand the significant forces and heat generated during braking. This housing ensures precise alignment of the caliper components for optimal braking performance.