Extech RF40 Battery Acid and Engine Coolant Refractometer

Highly Recommended
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.

A GREAT tool!!
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!

Convenience and Accuracy
Bought for use at my off-grid solar powered vacation home.

Much easier to take and record accurate specific gravity readings on my batteries. With this easy to use tool I'll be more diligent about watching out for my batteries' health.

Recommended.

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Extech RF20 0 Parts per Thousand to 100 Parts per Thousand Automatic Temperature Compensation Salinity Refractometer

Excellent choice
I'm using this unit to measure the salinity in my fish tank and for the first time I really know the real value of this important parameter. At first I was using a regular plastic hydrometer and was trusting the results I was getting, but then I bought a second hydrometer and the readings were totally different from the first one. That's when I realized that I needed more precision, and this unit is of course more expensive, but the accuracy you get is worth the extra money. It turned out that the salinity in my tank was way too high and was the reason for several problems I was having with the aquarium. The unit it's extremely easy to calibrate , all you need is destilled water and 10 seconds of your time, and is also very easy to use.

Dishonest seller -- NOT Extech RF20 refractor
I searched and searched looking for upscale instrument and thought this would fit the bill. I thought I was buying an very good quality refractometer judging by the reviews. I did not even bother to try it as it is no better than one for half the price. The package insert says nothing about were it is made, what firm made it, address, email, contact, anything. Save your money. You get the impression you are getting a higher quality instrument, but this is just a chintzy product with a case, like you would get buying a tool at Harbor Freight. Arrive poorly packaged for mailing too. Way over priced. Returning.
UPDATE: As I suspected: This is a Chinese knock-off. Below is the link to what you will get. It is NOT an Extech instrument. I have not heard from the seller. This hacks me off. Will ask Amazon for immediate refund.
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Well built meter
It showed up out of the box calibrated and hasn't needed any adjustment. The entire unit seems solidly built, and is very easy to use.

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Extech RF15 0-to-32-Percent Brix Portable Automatic Temperature Compensation Sucrose Refractometer

On the money!!!!!
I purchased this item 5-6 years ago. I use it once a year during grape harvest to take test samples of machine picked grapes and it has been accurate to .1 of a brix on every load that was tested. Taking your crop to a market that requires certain sugar standards in order to pass, this has been a highly valuable instrument and more than pays for itself after one season. Yes, I highly recommend this product, it has been extremely accurate in regards to the more expensive commercial type digital refractometers.

Great Product
Exactly as listed and in perfect condition. Does the job easily. Have a home set up and have spent a lot creating my own wine. This was an excellent price for great quality that works!

Awesome!
This thing is super easy to use, and so much better than a stupid hydrometer. Nice to be able to check SG quickly while sparging instead of waiting for samples to cool.

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