The file 'Star Trek Discovery Communicators 3D Printer Model' is (stl) file type, size is 15.3MB.
These badges use 4x 6mm x 1.5mm magnets.
Like these: https://smile.amazon.com/Linlinzz-Small-Round-Refrigerator-Magnets/dp/B06Y4SDHB8/ref=sr_1_1?ie=UTF8&qid=1508625200&sr=8-1&keywords=6mm+x+1.5mm+magnet