The box in which the 1/2" fittings are packaged does specify 1" in the instructions printed on the inside of the package. I have now obtained the official gauge. It does apply quite a bit more bevel on the end "de-burring" the end, but using it as a marking guide gives a mark at about 15/16", depending on how sharp the marker is. The on-line instructions tell us that the insertion should be to within .005" of the line marked from the gauge. I can't quite meet that tolerance. But, the insertion seems solid and positive, with additional force not giving deeper insertion. Moreover, I went ahead and tried the fittings on the actual rough plumbed pex, and experienced nary a drop when the water was turned on to those lines. I just hope the slight short-fall in insertion depth doesn't mean that longevity of the connection will be reduced.