Features:

  • SAFE&USEFUL--The unit are 2 pack Auto brake fluid tester.Check the health status of DOT3, DOT4, DOT5 car brake fluid, it will be safer for your driving.
  • EASY TO USE--The brake fluid tester pen is easy to use.Check the quality of brake fluid in car only takes seconds.Make it easier to operate for beginner.It's a must-have car tool for your car owners.
  • PORTABLE&DURABLE--Brake fluid tester pen is small compact size, easy to carry. Super strong ABS shell, has long service life.
  • 5 LED INDICATORS--5 LED to indicate percentage of water in the brake fluid with three colors green yellow and red. Even in the dark does not affect reading, make reading data easier.
  • AUTO TURN OFF--In order to save power, this test pen has the automatic shutdown function, it will automatically turn off the power 15 seconds after starting every time.
Pretty much does what the Amazon listing says... (per a homebrew calibration check)

Having seen some of the negative reviews of this product, I decided to do a relatively careful calibration check on the two units I received. I purchased a container of DOT3 brake fluid as a reference. I carefully cleaned and dried out a number vials of about 20 ml volume, with necks wide enough to accommodate the brake fluid testers. I placed 20 ml of clean brake fluid in a vial and used the tester to measure to read moisture content: they both read <1%. I flushed the tester probes with water and dried them, then added 1% of water to that vial, and repeated the measurement: they both read <1%. I flushed the tester probes with water and dried them, then added 2% more water, and repeated the measurements: one read 2%, the other read 3%. I flushed the tester probes with water and dried them, then added 2% more water, and repeated the measurements: both read the highest value possible, >4%. The bottom line from these tests is as follows: the little fountain pen testers do a pretty good job of detecting the presence of water in brake fluid, and -- at least the two that I have -- give a pretty decent idea of whether the level is low enough not to worry about it or high enough that brake fluid replacement is necessary in the near future. They are clearly not precision instruments -- which is to be expected for devices costing $7 each -- but seem adequate for me to decide whether I should replace my brake fluid. The only caveat regarding this is that measurement of the conductivity of brake fluid is not the Gold Standard, which is a direct measurement (by heating) of the boiling point of the fluid. From my personal view, I plan to do the following: (1) every year or so, check the fluid using one of my testers and replace if I see indication of 3% or more; (2) otherwise replace the fluid at the intervals specified by the user manual. This is not something that I represent as definitive or which I warrant is necessary/sufficient for anyone else to use as criteria for fluid replacement -- it's my opinion only. But I do think the little testers are reasonable instruments to use now and then to alert me to unusual changes in my braking system.

Seems to work just fine for a quick fluid check.

When you have multiple vehicles to keep track of, this will make life a little easier. Some vehicles seem to destroy brake fluid faster than others. Probably how the system is sealed, this is handy. One AAA battery, push the button, and insert probes into the fluid. The lights will tell you how good the fluid is or if you need to change it soon.

Great Tool for Brake Fluid

This tool was pretty simple to use to check the brake fluid in my vehicles. It was easy to place batteries into the device, and it is simple to use by clicking the button then inserting the probes into the fluid. The readings were pretty instant and easy to understand with the indicating lights. I honestly bought two to share with a friend.

Easy to use

Purchased the two pack so I could give to a friend since we both work on vehicles. Tested both vehicles I own and everything is in spec. I have no way to determine if it’s accurate but it works great for me but this will be a useful tool in my toolbox.

Great tool to have

This is a great tool/device to have around. Brake fluid should be changed periodically, and this item helps to decide when that time is. Seems to work great, and is handy in the pen configuration versus the larger ones depending on how much room you have to work with on your particular vehicle.

brake fluid tester

very useful and grateful to have it...

great brake fluid test

Great product but this tool is to test brake fluid and the plastic cap could of been made thicker and more durable

Works great.

Good price works great.

Handy tool

Super easy to use and useful for and DIY car owner.

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