Real ZDDP Zinc, not a substitute. Reduces engine wear. Reduces engine temperatures. Increases engine performance and life span. Allows modern oils work in older engines. Protecting engines since 1921. Rislone Hy-per Lube ZDDP Supplement (zinc dialkyldithiophosphate) is an oil additive designed specifically to protect older engines relying on zinc additives that are no longer found in sufficient quantities in modern oils. Works with both conventional and synthetic motor oils and both petrol and diesel engines. Older engines were designed around oils containing zinc to coat and protect moving parts. Modern oils have insufficient (or zero) zinc additives, and this causes accelerated wear, higher engine temperatures and a shorter engine life as a result. Protect your car’s engine with the best of both worlds – modern technology engine oil and ZDDP. Not for use in modern engines later than circa 2000. Do not use with catalytic convertor exhaust systems. One bottle treats up to 5L of engine oil.