Excellent tool. It is so nice to not have to print 50 different radius cards. This seems to be really accurate when I checked with calipers as well. :) Here printed in PCTG. (Should have probably chosen a brighter color for the indicator line on the black part, but it still works). It was a little bit sticky to move the gauge at first, but a small drop of silicone oil on the hinge in there did the trick and it is now smooth.