Unique. Whenever bearer makes an influence check, he must also make a corruption check. If the bearer is not a Hobbit: he receives +1 to body to a maximum of 10; he receives +4 to direct influence; and he may tap The Iron Crown to cancel an attack by Orcs, Trolls, or Men against his company.
"'If I had this thing now in the deep vaults of this citadel, we should not then shake with dread under his gloom, fearing the worst..."
-LotRV