This is a box, to hold things. It's designed to work with some 1/2"x1/8" diameter magnets such as these ones from Lee Valley. You get four magnets, and then you have a box that attaches itself to the side of metal things, such as fridges, gigantic laser-cutters, that kind of thing.

Doesn't Matter

Doesn't Matter

0.3mm

15+%

I printed this in PLA on a Makerbot 5th-gen using Simplify3D with no rafts or supports, 0.3mm resolution, and 15% infill. It worked great, although getting the magnets seated perfectly did require heating the PLA slightly to allow me to mold the magnet recesses a bit until the magnets seated.

I designed this in Onshape, which is awesome. The model is public. If you want to get an Onshape account, you can edit a parametric version of the model to adjust eg. box dimensions or magnet dimensions. Cool.