A simple and quick 'Bumper Case' for the Badgy, by sqfmi. The Badgy is an ESP8266 2.9" e-paper module, available on Tindie https://www.tindie.com/products/squarofumi/badgy-iot-badge/.
There are two files, one has a loop on both top and side, so you can loop this with a lanyard either horizontal or vertical. The other file (top_top_loops) has just the top loops, so it looks more like a wide lanyard badge.
Best to stick to 100% infill, it's only small and you'll be done in a jiffy!
There are little lips on three of the corners, one corner (top left) is missing. Slide the bottom right corner in, then pull the top right corner into the bumper. Then wiggle the bumper so the bottom left corner fits in. The top left corner can then just be pushed in and stays in with friction. A good printer will give you some good tight fits - mine have never fallen out!