Robo 3D Spool Resizer

I'm brand new to 3D printing, and this is my first attempt at modeling something and printing it, but it turned out surprisingly well so I figured I'd upload it since I couldn't find one someone else made on here.
When I first started using my Robo 3D with the spool that came with it, the spool kept falling off of where it should be on the spool holder, and created more tension for itself. In order to fix that, I made this ring to decrease the size of the hole in the center of the spool. So far it's working great.
The dimensions of this spool resizer are 2"x2"x1.2". I don't have any more spools, so I have no idea if this is the right size for any spools other than the 300g spool of test material that came with the Robo 3D Printer.

It should also be noted that I added a piece of duct tape around the outside of the ring to increase traction and make it fit a little more snug. You could probably increase the diameter by a small bit and make it for more snugly, but I didn't want to