HARD COAT ANODIZING
MIL-A-8625 TYPE III CLASS 1 OR 2 Sulfuric Anodizing

Class I is natural hard coat and class II specifies a color. Hard coat anodizing forms a heavier aluminum oxide coating than regular anodizing. Durablity is 10x greater and hard coat anodizing provides excellent lubricity. Average thickness for hard coat is .0005/.001 thick.