Can be attached to an Anti-dragon shield to create a Dragonfire shield. You can pay Oziach 1.25 Mil gp to attach this to an Anti-dragon shield, or you can attach it yourself, if you have at least 90 Smithing, and you will get 2k Smithing XP.
Black dragon, Frost dragon, Iron dragon, King Black Dragon, Mithril dragon, Skeletal Wyvern, Steel Dragon
Going from memory, they're what make a Dragonfire Shield. Add the visage to a Anti-Dragonfire Shield and BAM. They're mostly dropped from metal dragons if I remember.