STP oil additives have been helping engines withstand the toughest conditions. STP ultra 5-in-1 formula is scientifically engineered to enhance your motor oil's effectiveness. The product has been formulated to help maximize protection levels and performance. High-performance detergents and friction modifiers come together to form a one-source solution to help and save gas by deep cleaning the entire fuel system, restore peak performance, reduce friction, prevent ethanol deposits and inhibit corrosion.