This is a ID card holder for people who have more than 2 cards.  There is plenty of space in the front for up to 4-5 cards and then a spot on the back for 1 card.  I put my RFID scan card on the back and then depending on where I am I change the front card out.  

printed it with PLA, plenty strong.

I printed It standing up straight to minimize supports, but you can also print it without supports, it just makes the top a little weird, but it still works great, and saves on print time and filament.

Just updated the model, I added a radius to the top part that hooks to a lanyard, and a small radius to the “feet” of it for a little added strength.  

Been using mine for a few weeks now with no issues as long as you don't step on it; then it will break.  Just saying