KAIWEETS Brake Fluid Tester Pen with Corrosion Resistance Probe, High-Precision Brake Fluid Moisture Tester with Data Hold Function, Buzzer Alarm, 3 Colors Backlight, Calibrated for DOT3, DOT4, DOT5.1

I've had it for a few weeks only and used it on a handful of occasions. Its seems accurate for my purpose. It shows zero when dipped in a fresh brake fluid and >1% when testing a 2y old fluid. It is a plastic tool, but it looks sturdy enough unless one attempts to use it as a screwdriver.

Under 2% is good.2-3% is bad.Over 3% flush fluid ASAP.My results:2001 PT Cruiser: 2.5 (bad)2005 GMC Sierra: 1.7 (good)2007 Ford Ranger: 1.9 (good)

Over the years, admittedly I haven't been good about changing brake fluid. Normally I would only add when low as pads wear down, or change it out when changing brakes, or if it looks dark. But I've been reading more about the importance of keeping brake fluid fresh, as it absorbs moisture over time. When brake fluid absorbs too much moisture, you won't likely notice under regular breaking, but you might if you're coming down a hill and your brakes fade, or lose them altogether because the fluid boiled due to excessive moisture in the lines. Or, you have a failure in somewhere in the system due to rusting caused by moisture - something I never thought of, until recently. This could be a pretty scary thing to have to worry about, especially if you often carry a load. (which I don't)On the other hand, my new BMW tells me I have to change every two years regardless of mileage. That seems like an overkill to me. Manufacturers seem to vary in their requirements, so one has to wonder. Is this really necessary, or is it just another reason to get you into the shop more often than necessary? I don't live in a humid climate, so it's probably an overkill. If you live in the South Pacific, I'm sure it's not. But this brake fluid moisture tester should help with this.As others have said, this tool is very easy to use, gives an instant reading, and should save a lot of hassle and unnecessary expense. My only complaint about the tool is the annoying upside-down orientation of the display. And, it shuts off when you pull it out of the fluid. Otherwise, it seems very well designed and built. The instant color coding reading is very helpful and instantaneous.

I recently purchased the Kaiweets Brake Fluid Tester Pen for my shop, and it’s been a fantastic addition to my toolkit. As a mechanic, it’s essential to ensure brake fluid is safe and effective, and this tester makes the process quick and easy.The tester provides clear, precise readings of brake fluid moisture levels, with a simple 3-color backlight system that indicates whether the fluid is safe or needs to be replaced. The data hold function is a great feature, allowing me to easily show the customer the exact reading. It’s also calibrated for DOT3, DOT4, and DOT5.1 fluids, which is perfect for the variety of vehicles I work on.The corrosion-resistant probe is durable, and I love the buzzer alarm that alerts me when the moisture level exceeds safe limits. This tool has saved me time, increased accuracy, and improved the quality of service I provide to my customers. Highly recommend it for any mechanic looking for a reliable brake fluid tester

Easy to use to test your brake fluid. I used mine to test my old brake fluid and then tested again to check the new fluid after I had it changed. That way I know that the mechanic did their job.

Saved me from replacing my brake fluid!

Tested brake fluid on 3 different days and each time it came up with a 1.6 reading! No need to spend $150 for new brake fluid like the dealer suggested!

Functional: The product is easy enough to use. Accuracy: not sure, didnt order another to test against.Quality of life: If you are wondering when you get this if reading it is confusing, it is. The way the digital gauge represents the numbers is upside down. I used it, and was wondering what 1z meant...then realized I was looking at 2.1. Since the dot between those numbers is on the top when upside down, it really freaked me out that I thought perhaps my level reading was 12 at first glance ( might as well be water at that level).Value: meh.Size: I've seen others with a bendy tip which may be more useful than pen stick format, and you could have device orientated anyway. I give this a ok for size.