I wasn't aware this was still in my shop, it actually doesn't fit a Metrocard. My older version works perfectly though if you are interested:
Unfortunately you have to remove it from the case, I had intended it to be able to swipe whilst still inside but at 0.7mm (the smallest thickness Shapeways prints at) it is too thick to go through the reader with the card inside.
But it makes for a nice holder so you don't need to keep you Metrocard in a wallet or have it loose in a pocket where it can easily get damaged or lost. I used mine daily for two years until I moved out of NY and was extremely useful!