--Grade 8.8/10.9/12.9; --Black Oxide, Phosphate, Zinc Coating 1. QUALITY: Grade 8.8, 10.9, 12.9 .2. SURFACE PROTECTION: Black oxide with Protective Oil, Phosphate (Grey), Zinc Coating (Yellow/Silver) and Dacromet (Sliver).3. MATERIAL: 45#, 40Cr, 35Crmo (SAE1045, SAE5140, SAE4135) . wheel bolt and nut