This concentrate is then diluted with water to desired concentration, creating milky macroemulsion. Due to the presence of water in the emulsifiable oils some characteristics may occur such as corrosion, foaming or microbiological contamination, that is why variety of additives must be applied in the formulation including corrosion inhibitors, foam control agents and biocides. It is also important to ensure stability of concentrate and emulsion using coupling agents. To ensure lubricity in wide range of temperatures and pressures formulations usually contain boundary lubricity boosters and extreme-pressure additives.