SAE 20W-50 is a type of motor oil that is classified by the Society of Automotive Engineers (SAE). The "20W" indicates that the oil has a viscosity rating of 20 at low temperatures, making it suitable for cold starts, while the "50" signifies a higher viscosity of 50 at high temperatures, providing better protection in hot conditions. This oil is commonly used in older vehicles and high-performance engines, as it offers excellent lubrication and protection under various operating conditions. It helps reduce engine wear and maintain performance, making it a popular choice among car enthusiasts and mechanics.