Red Line's synthetic motor oils are designed to provide the highest protection, cleanliness, and superior drain intervals with the lowest friction for your gasoline, diesel, motorcycle or marine engine. Red Line uses the most stable components available and formulate their products for wear protection and friction reduction across a wide range of engine operating conditions. Red Line's products are unique because they contain polyol ester base stocks, the only lubricants which can withstand the tremendous heat. The Red Line 10W30 has Great all-weather viscosity grade for gasoline engines in cars and light trucks that are driven on the street on a daily basis. More power and economy while providing thicker bearing oil films at operating temperature than a petroleum 10W-40. Best choice to replace a 5W-30 or 10W-30, petroleum-based or other-brand synthetic oil if maximum durability is preferred. Acceptable for engines that are occasionally operated in extreme cold weather.