Interesting and well priced method to know the freatboard.
It comes with some theorie. Applying with the wooden stick goes well. I was applying one fret too high the first time, it was not really clear in the manual. When applied, it is a litlle harder to slide accross your neck and find your way visually. But if you want to see the notes on each fret, that's unavoidable. I also applied at the downside of the neck some extra tape, because I rubbed some stickers loose.
If you want to study some deeper for a while, then this is definitely worth trying for the small price. Not interesting for always on.