Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2317950.

This is the Iron Man Mark 46 Helmet from the Captain America Civil War movie.

I have not printed this helmet out yet but, I think if printed at 100 -105% it should fit an adult head. Check pdf file for dimensions. Units are in mm. If you do print this before I do, please let me know what scale fit your head.