The SAE values designate the viscosity classes of motor vehicle lubricants as standardized by the Society of Automotive Engineers (SAE). Example: SAE 0W typifies an extremely low-viscosity winter oil corresponding to the lowest viscosity class currently defined. By contrast, SAE 40 designates a high-viscosity summer oil. A multi-grade oil, e.g. SAE 0W-40 provides the same performance as SAE 0W in cold weather and the same performance as SAE 40 in hot weather. They cover the performance requirements for both cold starts at low temperatures and for driving on the motorway at high temperatures. A low cold viscosity stands for quick engine lubrication during cold starts and hence reduced fuel consumption. A higher high-temperature viscosity stands for a reliable lubricant film at high oil temperatures but also for higher fuel consumption. With advanced engine oils there is a trend towards achieving optimum fuel economy. When using high-quality base oils, a reduced high-temperature viscosity will also guaranteed a reliable lubricant film at all times.