The GATS jar is the only available portable fuel tester/sampler capable of separating non-petroleum contaminants (such as water, dirt etc.) from AVGAS. And unlike unreliable float-type testers, the GATS jar will also detect potentially fatal mis-fueled Jet A. A screen filter traps contaminants in the jar, allowing you to return the fuel back into the tank. This earth-friendly method stops the dumping of leaded fuel onto the ground.
Gats Jar Fuel Tester