Kolor Kut Fuel Finding Paste is the only gas finding paste approved by the US Military. It is used for checking the depth of fuels for Diesel, Bio-diesel, Kerosene, or Gasoline in fuel tanks. This fuel finding paste can be used in the petroleum industry to detect the presence of crude oil. The paste makes it easier to see the level of fuel when reading the measurement on a dipstick. To indicate the level of fuel the paste will turn from pink to red as soon as it comes into contact with fuel. This fuel finding paste does not expire and will always keep best when stored in a cool dry place with temperatures not exceeding 46 degrees Celsius or below -0.5 degrees.