Needed a outgoing mail flag for the new mailbox we built. Mailbox is plastic and didn't want to attach anything to the brand new brick.

Found a set of magnets here:

https://www.amazon.com/gp/product/B01M6B86Y3/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

Modelled up a base (base vertical.stl) for the magnet with a super glue on cap (cap.stl). Print the hollow opening of the cap and base up to avoid needing supports.

The flag (flag only.stl) needs no support if printed with the hinge up.

I printed the hinge (hinge.stl) horizontally on a raft due to its size and the layer lines I wanted.

Inside the lid of the mailbox I used black duct tape to hold a flat piece of steel to the inside of the lid.

When no outgoing mail is present, we store the magnet on the inside of the lid as shown.