Unique Kolor Kut Gasoline Gauging Paste works with a measuring gauge, rod or calibrated line to determine water levels. Apply the paste in the area that the level is expected to appear. When the paste comes in contact with water, it will immediately change from golden brown to bright red, marking the level. Gauging Paste determines levels of gasoline, naptha, kerosene, gas oil, crude oils and jet fuels. Paste wipes off easily after use and leaves no residue. 2.25-oz. jar.