This Yin Yang Cat fridge magnet and ornament uses a 10mm x 3mm magnet that we purchased from Amazon in a pack of 100 for about $10. The magnet can be glued inside the hole in the back with super glue or Goop that we purchased at Home Depot. We also added 4 ornament hooks so you can hang on your Christmas tree or wall. We included small, medium and large sizes of the standard cat, a thinner version and also included a cat with lower level whiskers and another with no whiskers or eyes (a true yin yang design). The cat with the whiskers can be difficult to print cleanly, and the whiskers can get knocked off if cleaning is required (although we added a support to tie them together and make them stronger). The thin version may actual look the best because you change the filament after just 2 mm height. On all other versions we were able to locate the magnet in the center of the design (instead of at the top) so it can be rotated in any position while on your fridge. Enjoy and Merry Christmas from the IEC3dDesignWorks team.