COOL SHIELDÖ coating - entire rotor surface including edges and vanes have baked-on zinc coating for durability and long lasting protection compared to uncoated Coated rotors will remain cleaner longer than non-coated Protective micron-thin layer helps to inhibit environmental corrosion better than non-coated rotors; proved in up to 200 hours of industry-standard salt-spray testing Some ACDelco Gold parts may have formerly appeared as ACDelco Professional Premium aftermarket replacement part Manufactured to meet specifications for fit, form, and function for General Motors vehicles as well as most makes and models Durability – ACDelco Silve Brakes are designed to help resist corrosion and premature wear