There is a version without embedded magnet spots and one with.
(!) If you want to embed magnets, make sure you look up how to add a pause during the slicing process. This varies by slicer. (!)
The current design is for cylindrical magnets, 10mm (diameter) by 5mm (height). There are four spots, but you can just populate two spots if you don't want such a strong magnet.
Make sure you check out the original model in case that's better for your purposes. It's an excellent model; I just wanted a solid version and wanted magnets in it.
The author remixed this model.
Made into a solid model with flat back, and a version made with places to put embedded magnets. Also resized to 160%.