Invulnerable Mail

Source
This item is crafted with Blacksmithing (300); taught by Plans: Invulnerable Mail, a world drop.

History
Due to the price and rarity of the Arcanite Bars required to craft this, very few people wanted to purchase or have it crafted. The armor itself was very good but the expenses could be sold and used to purchase something better and cheaper.

At some point, armorsmithing was removed as a requirement to learn the recipe for this.