Just got my hands on the Stanley Proto JFFCC3 antifreeze tester, and here's my honest take after using it for a while.

The good stuff first: It's super compact and lightweight, which makes it easy to carry around in my toolbox. I tested it on two different cars, and it gave me clear readings for ethylene glycol-based antifreeze, including Dex-Cool. The temperature compensation feature (both Fahrenheit and Celsius) is pretty neat too!

But... there are some issues. The numbers on the plastic housing rub off way too easily - I've only used it a few times and they're already starting to fade. Also, while it works fine for basic checks, it doesn't seem as accurate as more expensive tools when compared to known mixtures.

Would I recommend it? If you need something quick and simple for occasional use, sure. But if you're looking for precision or durability, you might want to invest in something better.