Jet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw colored. The most common fuels are Jet A and Jet A-1 which are produced to an internationally standardized set of specifications. The only other jet fuel that is commonly used in civilian turbine engine-powered aviation is called Jet B and is used for its enhanced cold-weather performance. Jet fuel is a mixture of a large number of different hydrocarbons. The range of their sizes is restricted by the requirements for the product, for example, freezing point or smoke point. Kerosene-type jet fuel has a carbon number distribution between about 8 and 16 carbon numbers wide-cut or naphtha-type jet fuel, between about 5 and 15 carbon numbers