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

Printer settings

• Top layers: 0
• Bottom layers: 0
• Infill: Honeycomb 25%
• Layer Height: 0.2mm
• Perimeters: 5