Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4611407.

• EDIT - 10/03/20: It was too big on the X and Y axes. * RE-UPLOADED! It was seriously 2mm too large in those dimensions.

^ That was frustrating.

• EDIT - 10/02/20: Well, I borked the Z measurement by a little under half, so... I've updated the Thing and fixed it. Also added: fillets in every corner to help further reinforce the walls! I know it's not entirely necessary because 3mm is /fairly/ thick, but it also looks nicer!

I'm leaving the short file up, but it was updated a bit to add the fillets around all corners! Even the flat ones are useful, I tell ya!

Yes, I know there are a metric crap-load of these here, but this is my first-ever project done in FreeCAD without being aided by a tutorial! Actually, I'm a bit proud of myself for it!

I needed something with specific dimensions, and Blender... well... kinda sucks when it comes down to accurate measurements because it's a visual-design platform [I'll have a bit of a ramble on this below, actually].

Included with the Thing is the FreeCAD file so you can customize it yourself! :)