Rislone Hy-per Lube Zinc ZDDP Supplement is a petroleum oil performance supplement "booster" containing ZDDP (zinc dialkyldithiophosphate). Zinc and Phosphorus EP (extreme pressure) additives help protect internal engine components including pistons, flat tappet camshafts, lifters, pushrod tips and the rest of the valve train. High performance formula stabilizes the motor oil to ensure against viscosity and thermal breakdown. Reduces friction and wear, especially at start-up, helping to eliminate dry starts. Less friction means less wear and a cooler running, longer lasting engine. Makes newer oils work in older engines.