This is a a holder for standard size cards (i.e. drivers license credit card etc.) It holds two cards one in a very tight fit, and another that can easily be slid in and out of place. can easily see 1 face on both of the cards or both faces of one card. sketchup file, stl, and a repaired stl are included if printing simply print the (repaired) stl.I printed at .1mm layers and 15% infill, can easily do 0% infill. No support is necessary The immobile card is a very secure fit and essentially it snaps into place, A modification to the file to make it 1-2mm taller might make a more comfortable fit.