Extech RF40 Battery Acid and Engine Coolant Refractometer Fahrenheit

Have been using it to test glycol strength in hydronic and free cooling systems. Have -20'F temperatures coming this weekend, so this will be a test for it.. if you don't see an amended review then you'll know it was "balls dead on".

As an RV tech, I use this tool to check the specific gravity of the house and chassis batteries on any RV that I am working on. Much more accurate than just using a DC Volt meter or hydrometer. Easy and quick to use. I can check all of the cells in just a few minutes. Highly recommended to anyone who deals with lead-acid batteries on a regular basis!

Very EASY to use and calibrate. This is a MUST HAVE if you use solar to power things in your home as you must check your batteries at least 2 times a year to see the overall battery health condition.

I work as a custodian for a public school system. The new building has a chiller system for cool air. I need to be able to monitor the glycol concentration for proper operation. The Extech RF40 comes with excellent instructions and is easy to calibrate and use. All this at what I feel is a very fair price.

we use this for our motor home in checking the antifreeze in our aqua-hot boiler , works well

This item met my expectations because I read the description of it before ordering. The only thing I wish is that the automatic temperature compensation would cover a lower temperature. Other than that, it has been working well.

Arrived on time. Seems well made. Works well. Reads accurate. Satisfied.

works great. packaged well. comes with an eye dropper and some other stuff.

If you have ever used a hydrometer to measure specific gravity of battery acid, radiator coolant etc... Do what I did.Close the bonnet of the car on it.Then buy a refractometer.Much more accurate (1% vs 4-8%) only needs 1 or 2 drops of fluid, and so easy to take a reading.A million times better than trying to read a floating hydrometer.When I am king, it will be illegal to use a hydrometer, and refractometers will be mandatory.I like it...

Just like I say, it worked well. With Extech, make sure you get the right one though! They can be hard to determine if you're looking to test battery acid, or coolant.

We live in an off grid solar home, where the systematic assessment of battery health is a No Brainer. This instrument is so much easier to use than the standard well calibrated hydrometers, and appears to agree quite well with their findings. It certainly saves on performing neck twisting contortions and questioning one's eyesight, in a tightly configured battery box. I have essentially retired my fleet of hydrometers, in favour of the Extech.

Very easy to use. Comes with dropper and distilled water for temperature compensation. I use it to check the electrolyte for my solar battery bank. Highly recommended

First time I've used it it wasn't clear where the line is. Thus I could not tell what temperature the mix is good for. The other thing is that I was hoping to have a tool that can read directly the percentage of mix, glycol vs water.