I had to do a search for what annual cutter is...
An annular cutter (also called as core drill, core cutter, broach cutter, trepanning drill, hole saw, or cup-type cutter) is form of core drill used to create holes in metal. An annular cutter cuts only a groove at the periphery of the hole and leaves a solid core or slug at the center.
In over 50 years of gunsmithing I have never needed one of these kits.
What are you going to do with it and firearms?