TRZ 4-in-1 Refractometer Ethylene Glycol, Propylene Glycol in Automotive antifreeze Fluids(G11,G12, G13) freezing temperature and concentration, automotive and industrial battery Fluid, DEF

This is the best way to check concentrations. It is easy to use and is pretty durable.Be sure to buy the version for the type of antifreeze you are using.

I was impressed at how easy it was to use, and much more accurate than the floating ball anti-freeze testers.

this is one of those tools that you wont use that often, but when you need it well it definitely comes in handy. I bought because I am a mechanic and need to check the DEF in trucks for contamination. Its well built and will last forever as long as it is taken care of.

It works fine, is accurate as near as I can tell. I wish it had a side scale listing a general specific gravity to correlate the other readings, but it is purposed for automotive use, and is perfect for that!I also think the case could have been just a bit more robust - it's kind of important for a fairly delicate instrument like this.All in all, I'd recommend it to my friends.

Excellent product for the money. One important thing to realize, regardless of which brand of refractometer you purchase, you must check the calibration before you use it. The manual mentions that it comes calibrated from the factory. Although they may have calibrated it before it leaves the company, it's easy for them to become un-calibrated through shipping. I've included a before and after picture. One represent how it arrived to me (un-calibrated), and the other is after I calibrated it. Calibration is incredibly simple to do.

Very easy to use and highly accurate for glycols. The scale is very visible and the tool seems durable for solid.

it does not rate fluid to a standard of composition-makeup- i think you know if you have solids in your DEF tank. i thought it would rate quality of mixture not measure contaminant solids-my mistake-

works well and is a good compromise of cost versus value for user. For the home user it is less then what NAPA retails. OF course if one is a professional then get what will hold up to that environment. otherwise I would recommend it.