Brake Fluid Liquid Tester Pen with 5 LED Indicators, DOT 3 DOT 4 DOT 5.1 Brake Fluid Liquid Tester Pen, Auto Brake Diagnostic Testing Tool Analyzer, Universal Car Accessories

I wanted to test the brake fluid on my vehicles as I suspect it will need replacing soon..I needed a AAA battery as it's not supplied. The battery cover is just pressed in place even though it has an arrow on it..I tested it in water and it successfully indicated greater than 4%. In a fresh bottle of brake fluid, <1%.My fluids were all around 2%. Okay but will need replacing soon..For $5.89, I'm not complaining. It works perfectly and is great value!

I tested two cars, one I changed the fluid about 8 months ago and the other one month ago. Both read as I would have expected, so I don’t have any reason to question its accuracy. Quick, simple test for <$10 buys some peace of mind.

Nice to have in yer auto toolbox but it’s accuracy is unknown.

Fair price

Simply works as it should.

My 2021 Cadillac XT6 has 40k on it. I thought I’d test my brake fluid and see how it’s surviving. I got the green light for absolute goodness. I exchanged it anyway, it’s just something I do every 40k. Always playing it safe with my vehicles.

Haven't had a chance to use it yet, so can't say one way or the other.

The media could not be loaded. This is fast and easy to use. Display is bright. Performance and quality in terms of accuracy is hard to measure. It can definitely tell the difference between brand new fluid and water. Those results were exactly as your expect. On my used fluid, the results ranged from 2-4% and I took several tests to conclude the mode reading of 3% was probably fairly accurate. For the price it's a reasonable value even if not professional quality. Battery required is a single AAA, and the re-closable bag is a good place to store both between uses.