Edge Angle, Angle Guide, and Blade Body Angle

[grepper]

I have one of those things too, but mine is only accurate to +/- 1° so I never use it.  The one you linked to is Accuracy: +/- 0.2° .  There is this one https://www.amazon.com/Johnson-Level-Too...HPTB2JSBW3 that claims accurate (±0.1).

For all of the electronic versions it might be good idea to check them against a physical angle block to see if they live up to their claims of accuracy.