Octagon that holds up to seven bits that attaches to a keychain. The bits can be easily used from around the outside but can also be placed into the centre for a different grip. There's a tight fit so the bits don't fall out and get lost, very secure.

I recommend having 3 or 4 perimeters and a little extra infill to make it stronger. Prints well at regular 0.2mm layer height.

I added the gcode file I used for my Prusa Mini+

I printed it in PLA Prusament Galaxy Black