I guess if you had similar size samples of real, fake and man made specimens to compare your results to it would be a better tool. But if you don't have that you can not be sure what you are looking at because calibration seems to be a critical part of using this tester. Instructions are written is spotty English and hard to follow. I would not base a real or fake test on the results of this tester unless I had known specimens to back check results with. May or may not be worth the price.
The tester is good , just The manual don’t explain very well how to calibrate , then they tell you about points in the diamonds , if you aren’t a especialist in diamonds is really difficult the interpretation