Would not calibrate properly. Got a replacement and it also would not calibrate properly. Took it to a friend that was very familiar with refractometers and the problem seemed to lie with the alignment of the prism in such a way that the cover lens could not lie flat on the prism. Returned and requested a refund and ordered ebayโs choice refractometer and it calibrates and works fine. I suspect the first two I got that would not calibrate properly were from the same batch and most must work fine according to the number of positive reviews.
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