Review on Calibrated ITEQ Brake Fluid Tester Pen With 5 LED Indicators For Accurate Testing Of DOT3 And DOT4 Brake Fluids by Tommie Lawson

Bought it to check if my really old brake fluid in my truck needed to be changed. After inserting a AAA battery, I did what others had mentioned and dipped the two probe tips into a cup of water and it lit up like a christmas tree (as expected). I then dipped it in brand new brake fluid and iirc, it either lit up one or no LED dots (again, as expected- since there shouldn't be any water moisture in a brand new bottle of DOT3 brake fluid where the foil top was just removed.) Now, after cleaning off the probe tips, I then dipped it into the truck's brake fluid reservoir BEFORE adding and topping it off with new brake fluid. To my surprise, it lit up (2) LED's indicating 1%-2% water moisture in it- but not bad enough to change yet. I did buy the brake fluid litmus test strips to cross check the results, but haven't gotten around to doing it yet. As such, I am giving 4 stars for now. I plan to revisit this review after the strip test is done, as well as after some time has passed since others have mentioned that their test device had stopped working after a few months. I'm glad that my brake fluid is in the 'safe' zone for now, but I know that the fluid hasn't been changed in years (I know, shame on me). So far, it's another electronic gadget to help with car maintenance.