Identify Tool
 

Purchased tool box full of bicycles tools identified most but this one anyone know what is and for what purpose.Thank you.
https://cimg5.ibsrv.net/gimg/bikefor...00d71157d.jpeg

Suntour freewheel sprocket spacing gauge. "Regular" refers to 5-speed and normally-spaced 6-speed freewheels. "Ultra" refers to the Ultra-6 freewheel, which introduced the notion of stuffing 6 sprockets into the same space traditionally taken by a 5-speed freewheel. Probably applies to other, newer "narrow" spaced freewheels (and possibly cassettes) as well.

No idea what the black wafer is for. Does it have anything stamped on it?

^^^ Beat me to it! For some reason I have a set of these in the package.... somewhere!

That is the coolest key chain I have seen in a long while!

Black one is stamped Size (1st-2nd) (2nd-3rd)