In my case these slots came loaded with three differently sized hex wrenches that fit the the various screws on the gen. 3 pro.
Now I can sleep peacefully knowing what those slots are for. 😀
Anyway my initial impression of the Gen 3 2017 is absolutely awesome. I can’t wait to sharpen with it. So happened I have a new blade I need to sharpen. I’ll post my findings if time allows.