High-quality replacement hardware from StopTech. These precision-engineered washers are designed for use with Jet Nuts and ST-22/ST-45 caliper mounting bolts in StopTech High Performance Brake Systems. The hardened construction ensures optimal load distribution and prevents loosening under high thermal stress and vibration. Product specifications: - Outer Diameter (OD): 18mm - Inner Diameter (ID): 12mm - Surface Finish: Zinc Plated / Anti-Corrosion Coating - Application: Specific to StopTech Big Brake Kits (BBK) Kit contents (Single Item Part Number 40.220.0001): - 1 x 18mm OD / 12mm ID Precision Washer Note: For a full axle overhaul, ensure you order the required quantity as specified by your caliper bracket mounting guide.