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

Works great! Only $6. What a great value!

It does work and it’s easy to read.

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.

I was highly skeptical that I needed one of these in my life. Then I opened up my brake fluid which was supposedly being done at the dealership for the last 3 years and it was green. No not black, green. Yes that's right, the brake fluid was green. I'm talking green like Green Eggs and Ham , yes Sam I am. I threw the test pen into the master cylinder and it said 4%, which I guess is red for dead. This is the easiest thing to use in the world, you click the button unscrew the master cylinder throw the tester into the brake fluid and look for the light. You have a 5 position light that indicates what percent the amount of water in the brake fluid is. Green for go, yellow for warning and red for dead. Looking at the brake fluid you could clearly tell it was very bad so obviously the tester itself is accurate. The build quality seem sufficient for what it is, it does not say it is waterproof so make sure to only immerse the testing probes. I recommend not storing a battery in the pen if you're going to not check anything long term. Oh yeah you need 1 AAA battery that should last forever. Now I'm spending $200 on Amazon for an automatic brake flushing machine so I never have to pay the dealership again. You should too, It'll help the economy.

Tested on two bikes, at home at the same time, Harley shop concurred to same readings.

Does the job and good price

I am a DIY, basic maintenance type of person: oil changes, brake and rotors, filters, etc. I have always wondered when to flush the brake fluid. Being hydroscopic, brake fluid will need to be changed, but you cannot just look at the color and know the time has come. This little tester has allowed me to better keep check on the fluid health. Highly recommend!

I couldn't tell you if it worked or not. I tested several vehicle and all of them were older than 10 years and it gave same reading on everyone. Is it defective? I'm unsure. Would I purchase again? Probably not. Is it worth the price? I would say yes. If it detects high moisture in one vehicle, it paid for itself many times