Invulnerable Mail

Source
Invulnerable Mail is crafted by Blacksmiths with a skill level of 300.

The components are:
 * 30 Arcanite Bar
 * 30 Enchanted Thorium Bar
 * 6 Huge Emerald
 * 6 Azerothian Diamond

The plans drop off creatures in their levels in the high 50s and low 60s.