Inner Diameter : Front to back 9. Use this Helmet as a great Halloween Costume. The item "3 Piece Medieval Greek Corinthian Helmet WithLong Plume Athenian Spartan Costume" is in sale since Monday, April 15, 2019. This item is in the category "Collectables\Blade Accs, Armours & Shields\Armour & Shields".The seller is "medievalmuseum" and is located in HARIDWAR. This item can be shipped worldwide.