Found a few different styles of files. The typical ones have one or two rings at the base ( 15/45 for the red ones for example). The charts I had that came with the Endo Box didn't list others. The fatter files had 3 rings spaced in the middle.
Now I found skinny ones with four lines (the silver) and fat ones with single/double cuts at the top of the file ( gold/blue/red).