This is a bumper for the Adafruit Trinket micro-controller. Actually, its a bit more than a bumper since it actually has a back to it, not just the sides.

This was designed to work with Ninjaflex filament which will stretch to fit onto the trinket and grab onto the trinket elastically. I've provided a slot for the USB receptacle and holes just in case you either add headers to the trinket or want to access its I/O ports from the bottom instead of the top.

I've also included pegs to fit into the trinket's mounting holes but these can be snipped out if you don't need or want them.

Here's a link to the Adafruit Trinket - Mini Microcontroller. This should work for either the 3.3v or 5v version:
https://www.adafruit.com/products/1501
https://www.adafruit.com/products/1500

Doesn't Matter

No

0.2mm layer height works fine

100%

I used Ninjaflex for this - it may work with PLA but I believe it will be just slightly too small to fit the Trinket if you use a rigid / inflexible filament.