The Prolong Super Lubricants 15W-40 Diesel Motor Oil features the company's proprietary anti-friction metal treatment. This technology is designed to bond to metal surfaces and create a protective layer that reduces friction, provides excellent wear protection and increases fuel efficiency, according to the company. Formulated with a blend of high-quality synthetic base oils and additives, Prolong's 15W-40 Diesel Motor Oil is designed to exceed API Service Classifications CJ-4/SN/SM. It is available in one-quart and one-gal bottles, five-gal pails and 55-gal drums.