Generic card holder and cash clip add-on

My leather wallet recently died, so I figured I would print one. I settled on this design:

https://www.thingiverse.com/thing:123670

The only problem I have with it was that my public transit card would not be read through it. I had to find a solution to either bring the card closer to the reader, or make it easily accessible.

I decided to design this generic single card holder with an integrated cash clip to solve my problem. It can be glued or welded to any other printed wallet or thi