This is a simple card holder that I use to hold 9 various size cards. If your cards are thicker you may not get 9. One of the cards that I carry is a RFID blocker like this: https://www.amazon.com/D-Armor-Wallet-Blocking-Protector-2-cards/dp/B00CJHZLEW
I print it standing with supports. Be careful when removing supports from the back so you don't damage the top part of the money clip.
The opening on the bottom is to assist you in pushing cards out.
I have been using the black one daily in my front pocket for the last 3 months.