QCS is for use with fuel-tester (complete test kit) and/or can be used alone to verify gasoline is ethanol and water-free.
(EG. Marine, Aircraft, Diesel and other specialty type fuels). Note: Even very small amounts of alcohol and water in tank will reveal a positive result. Very helpful to quickly check at gas pump, to avoid purchase of contaminated gasoline.
We recommend purchase of the fuel-tester with QCS, so that when results are positive, transferring fuel sample to tester will reveal alcohol percent - If 0% reading you know positive result is due to water; If tester reveals alcohol (2%, 5%, 10% etc.) most likely the quik-check positive is due to alcohol (can be due to both alcohol and water). When fuel is contaminated with water it always will appear cloudy/hazy (not clear) and may also be phase-separated (2 or 3 distinct separate) layers on visualization.
* Exclusive product created by Fuel-Testers Company in 2006. Not available in retail stores. Beware of imitations that are ususally just a bottle of cheap food coloring dye.