1. Fill the TESTER with water to the "Water Fill Line".
2. Fill the TESTER with the Gasoline or Alcohol to the top edge of the bottle.
3. Reapply Cap to TESTER and Firmly tighten - To avoid any leaking liquid.
4. Shake the TESTER until contents are fully blended (or suspended).
5. Rest TESTER on a flat surface and let the contents (Gasoline, Alcohol and Water) settle out of suspension.
6. Any Alcohol/Water present will appear above the "Water Fill Line" and under the Gasoline that is present above it.
7. The volume present above the "Water Fill Line" will represent the total percentage of Alcohol/Water present in the Gasoline or Alcohol that was tested.
8. When test is complete simply pour out contents, allow TESTER to air dry. When dry, reapply cap and the TESTER is ready to be used again.