SWEPCO 306 Supreme Formula Engine Oil is a premium quality, extended service, heavy duty engine oil that exceeds the requirements of most over-the-road major diesel and gasoline engines manufactured prior to 2007 and off-road diesel engines manufactured through 2010. It is a superb, energy saving blend of the highest quality oil stocks with the latest lubrication additive chemistry, including SWEPCO's proprietary friction additive, DIMONYL. Provides safe, reliable, long-term protection from friction, wear, oxidation, sludge, varnish and corrosion and offers important cost effective benefits.