In Wrath of the Lich King it is item level 245, requires level 80 and is named Worldbreaker Chestguard. In MoP Classic it is item level 232 and requires level 80.
Read from the World of Warcraft client build files.
How Conqueror's Worldbreaker Chestguard Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Conqueror's Worldbreaker Chestguard suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Transmog Sets
Conqueror's Worldbreaker Chestguard is part of the transmog set Conqueror's Worldbreaker Regalia (Shaman only). The other 16 pieces:
Items Numbered Next to Conqueror's Worldbreaker Chestguard
Blizzard numbers items as they are created, so the named items next to ID 46205 (46200 to 46210) were usually added in the same batch as Conqueror's Worldbreaker Chestguard: the same quest line, zone, vendor or reward set.