Review on Enhance Precision: Apera Instruments AI1113 Calibration Polyethylene for Accurate Measurements by Richard Alemayehu

I've had something like this before and it worked fine, but I noticed something was wrong with the 4.0 solution when I started getting calibration errors. I have an expensive Bluelab stylus so they don't have this type of problem but I bought a replacement thinking it was a stylus but it wasn't. I got a replacement grip but still had errors with my 4.0 solution. Then I noticed something was floating in my 4.0 solution bottle when I was only a few months old, but 7.0 was still fine. So I thought something was wrong with my 4.0 and ordered more. Then I got the new 4.0 but still get errors on both the new and old grips. But still 7.0 worked fine. Makes me think something is terribly wrong with the 4.0 solution set. Also, the seals on both bottles were loose. I would buy another brand until they check quality control.