Straight Grade Mineral, Break-in Oil in Aviation Grade 120 is primarily used in aircraft that do not require a dispersant additive (AD). These oils are used to break-in new engines or overhauled engines before actually committing to normal operation, wherein another oil should be used.
These oils allow for controlled friction to begin to wear away at engine components, but in such a way that the engine will be able to prepare itself for flight. Please note that these oils are not intended to be used as lubricants for normal operation and flight.
Straight 120 Grade Mineral, Break-in Oil is commonly used as a break-in lubricant in 4-stroke aircraft engines and antique airplanes.