Hy-Per Lube Zinc Replacement Additive - 12 oz. Provides Superior Wear Protection Even When Added to Oils Containing Reduced ZDDP Levels Maintains a Strong Oil Film at High Temperatures Reduces Cold Start Wear After Long Periods of Shut Down Environmentally Safe, Contains NoHeavy Metals and Will Not Harm Emission Controls or Catalytic Converters Compatible With All Motor Oils Including Synthetics