My faucet has an embedded aerator so I can't unscrew it with my hands, you need a specific tool. My tool is ~18.5mm of diameter so I created it for mine. If you have a similar faucet it will probably help you. I printed it with this config:

• 0.16mm layer

• brim

• no supports

EDIT: Someone told me that in Prusa Slicer or in Orca Slicer it imports it as microscopic so I fixed it (v2), I think now is ok