Heavy duty 12 gauge hand made black hammered Umbro. 8 inch diameter (23mm) hemispherical cup allowing more room for gloved hand, steel. 2.5 inches deep (63mm). Six predrilled holes to easily fix to shield. This shield boss is just what you need if you are a reenactor who is making or repairing your own shield. Weight 800 grams Also known as an Umbro, designed to deflect blows from the centre of the shield and provide a place to mount the grip of your shield. Common place on Roman, Viking and Saxon shields, Used with a punching motion to block attacks. Will take one heck of a beating. .