ZKTOOL Upgraded Version Automotive Brake Fluid Tester Pen, 5 in 1 Detector, Can Test DOT3 DOT4 DOT5 ENV6 ENV4, 5 LED, Universal Brake Fluid Oil Detection Pen, Brake Fluid Moisture Analyzer

It works well it's a handy tool to have. You don't know what the condition of your brake fluid with out some form of tester. It works well

Appears to do the job it’s supposed to, simply and quickly. However, without comparing the results with another tester no way to confirm the accuracy. If the results are accurate will pay for itself easily by extending the period before replacing the brake fluid

Good piece of equipment needed in a garage

Works perfect ! Very usefull tool to have.

Perfect for me

I dislike being prompted to write a review when I have barely had time to open the package, so this rating might change. If this device is accurate it could merit 5 stars. Perhaps it is. I tested one of my cars a couple of days after the fluid was renewed and sure enough it read 0% water. I tested a second car that I know has not had a change for at least 4 yeaes and got a 0% reading from that. A third car came up as 3%-4%. I don't know when that was changed but it is a deeper colour which usually indicates older fluid. So it could actually be telling the truth. Be aware that you need to set the fluid type. I don't know how one can know this if one didn't put the fluid in ones self. Most cars would be happy with DOT3 but most fluid on sale now is DOT4 that meets or exceeds DOT3 requirements. So I suggest assuming it's DOT4. Garage test machines are £200 or more. Maybe this is because they actually test the boiling point? New DOT4 boils at circa 260C apparently. This drops to around 160 with 3% water. I only know personally of 2 people who have boiled their brake fluid. One is my brother who did it over 40 years ago in a car with probably 13 year old dark brown brake fluid. The other has a Porsche 911 with recent fluid that is almost clear. But by the law of averages most of us probably be ok if we drive sensibly. Assuming it's working ok, the only criticism I have at this price is that it automatically shuts off too quickly. Does that help?

Wow what an amazing tool so handy easy to use a must in anyone's toolbox

Seems to work ok but it fell apart in my bag so its a bit flimsy. Stuck it back together with superglue and it seems to still funtion ok.