Lord of the Rings Elven Helmet from Rivendell.
This is meant for medium to possibly large sized heads, I am 22 years old, 160 pounds, and 5'11, and this is adjusted for my head well, although larger may need to be sized up a bit.It comes in a full size, or a split size for smaller printers (256x256). Below that and you may need to split the helmet more. The fin at the top of the helmet nestles into the helmet nicely, and I would just recommend sanding it down a bit and using either strong glue and/or some Tamiya cement before inserting.
If anyone has any problems, feel free to let me know and I'll do what I can to assist you.