O-Ring for Card Shooter

This is an O-Ring that fits the Playing Card Shooter by LoboCNC, which can be found here:
https://www.thingiverse.com/thing:961084
Not sure if this is technically a remix, really it's more of an addition.

I ordered the skate-bearings off amazon, but thought I might be able to print the O-Rings with flexible filament rather than buy them. It worked great!

I use this card shooter in my trig classes when we are talking about angular speed and linear speed. The lesson is here: https://gras