It is the author's vision based on interpretation of the book of George Martin.

The crown has an oval inner diameter 7.5x6,5 inch (19x16,5 cm).  Oval diameter fits well to one's head. 
The crown is packed in a wooden box for careful shipping and storage.

If you need a different diameter please just let us know your preferred dimensions.
If there is anything we can help you with, please reach out in messages. We’re always in touch!