Genuine OEM Volkswagen Socket Head Bolt, part number N91183701. This high-strength fastener is designed for securing critical components within the brake system, specifically the brake caliper. It is located at position 20 in the provided diagram. The bolt is engineered to withstand high thermal and mechanical stress. Genuine OEM fasteners are essential for brake assemblies to ensure the correct torque retention and safety-critical clamping force required for reliable stopping performance.