The auto ignition temperature of burning cooking oil is higher than other typical combustible liquids so the standard Class B foam fire extinguishers and dry powder extinguishers can be ineffective. This lead to the development of specialist Class F (US class K) fire extinguishers for cooking oil fires that use a chemical reaction called saponification to put out cooking oil fires. Commonly termed Wet Chemical extinguishers they use an alkaline solution which reacts with the cooking oil or fat to make a non-flammable soap. Once only found in commercial and industrial kitchens Class F and the versatile Class ABF versions are now available in smaller canisters and disposable aerosols for domestic and leisure markets.