Premium quality marine diesel engine oils, designed for use in medium-speed trunk piston engines. They provide superior wear performance, cleanliness and stability on powertrains that operate on distillate fuels. They maintain engine efficiency. Suitable for highly-rated, medium-speed diesel engines operating under high load conditions and operating on distillate fuels of up to 2% sulphur content. They may, also, be used in other marine applications, including gears reduction systems, where specialist lubricants are not required.