Semi-synthetic gear oils are lubricants created by mixing mineral and synthetic base oil. The aim of this combination is to blend the properties of both types. The mineral component ensures basic lubrication capabilities and is more cost-effective, while the synthetic component enhances the oil's key parameters. Thanks to the synthetic additive, these oils have better thermal stability, meaning they retain their properties longer even at high operating temperatures. At the same time, they maintain good fluidity at low temperatures, which facilitates shifting, for example, during the winter season. They are also more resistant to oxidation, which is a process of chemical degradation of the oil causing its aging, and thus provide a longer lifespan than purely mineral oils.