I'm using this design to encase old credit card sized hotel room keys I've repurposed for use as NFC tags that trigger home automations.
There are two versions of the model, a single sided slide over cover, and a double sided click together cover.
The model is intended to be printed with an infill pattern and zero top and bottom layers
The OpenSCAD models includes parameterized settings to add custom text. A stencil style font should be used for the best results. For example Allerta Stencil available from Google Fonts.