This is the Windproof card holder I designed for my sister to use at outdoor events to prevent her business cards from getting blown away in the wind!

this design should accommodate a 3/8ths thick stack of cards and has a rubber band powered flap to hold the cards in place!

I used a 1 inch rubber band but feel free to try different sizes for different tensions

Print two of the "pin" parts, these should insert into the slots in front of the flap to secure it to the model, I've had some issue sizing them so play with the scaling if the wont go in, mine fit pretty tight and i cut the bottom flush with the base to prevent wobling.

I designed this with 3D printing in mind so it should print with minimal support, slicers will want to put support in the channel for the rubber band but it is only a 10mm gap so it should print fine without it, the overhangs for the flap-pins will need support, so unless you can add support blocker like in Cura I would leave it on

the openings and platforms in the back are intended for additional weight if the holder itself is not heavy enough for your needs!

all the parts should be scaled and placed correctly, but if it inports wrong for any reason make sure you are inporting in mm or scale up by 10

Update:
I've added new base files, these eliminate some uneeded material from the print, the ALT file has a lot of material cut away and reduces print time by nearly 2 hours however it does not retain the support for additional weights. The orignal base file was also replaced with a few minor edits and some material elimination.

these are both untested so let me know if they cause problems