I have two sets of sim cards - one for each side of the world, and this simple case keeps them relatively secure in my passport wallet.   It's about half the size of a credit card, big enough to avoid being misplaced, small enough to take up minimal space.

I've printed the tray with a 0.4mm nozzle in PLA and 0.2mm layer height, and the case with a 0.6mm nozzle in VASE mode (USE A 4MM BRIM to save heartache on this).

If you want to print the case with a 0.4mm nozzle you may wish to scale it in the slicer to compensate for the slightly smaller clearance, but use a brim as well.  

NOTE: Community Member Even_constant has posted a make using a 0.4mm nozzle in vase mode with PLA+ and suggests shrinking the width (longer edge) to 98.5% and depth (shorter edge) to 77.55% to get a snug fit. The height (longest edge) of course stays constant.