Synthetic fluids are the only type of MWF that do not contain mineral oil in any form. In general they can be diverse into three different types: solution synthetic fluid, emulsified synthetic fluid and straight synthetic fluid. In the first kind of synthetic fluids water is used and water soluble additives and it is then diluted with water to desired concentration. Emulsified synthetic fluid is based on base stock such as vegetable oils or synthetic ones and contains also additives known in previous examples: emulsifiers, corrosion inhibitors etc.; this concentrate is then diluted with water. The last type which is straight synthetic oil is similar to emulsified synthetic fluid but it doesn’t contain any water and it’s not diluted.