Verify ethanol free fuel E0
Fill with water to water line
Fill with fuel sample to the neck of the vial
Install cap and shake vigorously
Let mixture rest for 10 minutes
Look for the milky layer above the water line
This is your % of ethanol
Zero layer equals E0 ethanol free
Testers are reusable
3" (76.2mm) long glass laser etched
Made in the USA