Opti-Lube XPD and Opti-Lube Summer and Winter Blend are ranked as the best diesel fuel additives in independent studies (Diesel Place, Diesel Power Magazine). Opti-Lube products are completely compatible with ULSD and the latest emissions systems, including 2015 vehicles. For over 15 years, Opti-Lube has been extending equipment & vehicle life through improved lubrication. From vehicles to power plants, Opti-Lube products are chosen to reduce wear & lower energy costs. Explore our site and find out how Opti-Lube advanced lubricants can save you money. Also check out our GENERAL DIESEL INFO PAGE.