I should first point out that I've broken two of these. The first I chipped a small triangular piece out of the top. I continued using it for a while after that, treating it as if it was an inch shorter. Today I have broken my second one. As it was sitting on the counter, I caught the top of it with an empty drinking glass. The top couple inches of the test jar broke off.
That being said, I'm preparing to order my third. I also have a plastic test jar that I keep around as a backup, but I greatly prefer a glass jar. Yes, the glass is thin. Be careful with it.
The plastic base does have some flex, but I view this as a good thing. I can seat the glass jar in it, then adjust it slightly until it is vertical and the hydrometer floats nicely in it. In my plastic jar with the screw-on base, the threads attached to the jar were put on crooked, so it never sits squarely, and provides no way to adjust it.
If the glass were thicker and/or more durable it would get five stars. Otherwise, I'm pleased with it.
Reviewed by: Detrick Merz