Mira 10W40 is a mineral based high performance universal motor oil for heavy-duty engines with and without turbocharging. This lubricant meets or exceeds a great number of leading OEM specifications and therefore is a perfect multi-functional motor oil for mixed fleets. Mineral engine oil is where motoring lubricant started (in monograde form) and is very popular, it can still offer extremely high quality, however due to its lack of advanced blending and base stocks, these days it's generally recommended for the more basic engines. Because of this simpler blending and base stock it's a lot easier to produce, that's way it's generally so much cheaper than synthetics.