The Acustrip ACU 44863 Series Oil in Water/DEF Test is used to determine if there has been contamination to the diesel exhaust fluid (DEF) tank. Simply remove the DEF from the tank using a syringe prior to the strip being immersed and agitated. The intensity and size of the discoloration are indictative of the quantity of contamination by hydrocarbons (i.e. Petroleum, Gasoline, or Oils). The presence of hydrocarbons causes a chage in the color of the test strip. This kit includes 100 with a vial and syringe.