This Twin-Pax is available online and contains quantity required for 4 average oil changes. ProMax performance additive is quick and easy to use, just pour it right into the engine crankcase. Recommended mixture is 1 part ProMax to 10 parts motor oil. (1:10) Do this as part of or in between oil changes. Then add the same amount each time you change the oil. The vehicle manufacturer’s recommended service schedule should always be followed. Safe to use in wet clutch transmissions such as Harley Davidson. Use in gearboxes, V-drives. and manual transmissions