Briggs & Stratton Synthetic 4T Racing Oil is the brainchild of a joint effort between Briggs & Stratton* engineers and AMSOIL INC. Briggs & Stratton came to us with a request: develop a motor oil capable of maximizing horsepower while handling the intense heat and shearing forces inside its competition four-stroke engines. Synthetic 4T Racing Oil is the result. It's specially engineered for competition engines without the shortcomings of automotive, PAG or conventional "karting" oils. It's perfect for racers who want to get the most horsepower and longest life from their engines used in kart, junior drag, quarter midget and other racing applications.