A push pin style magnet that is perfect for the refrigerator or anywhere else you may hang thins up using magnets. This one is sized to use the smallest magnet of this set I purchased on Amazon:

https://www.amazon.com/dp/B09TB2JKBS?psc=1&ref=ppx_yo2ov_dt_b_product_details

This magnet has a radius of 4mm and height of 2mm. You will need to pause the print at layer height 3.20 to insert magnet then continue printing.