This WoW set features the full Valorous Dreadnaught transmog, which is the warrior tier 7.5 (25-man) raid set. Dreadnaught is obtained by looting Wrath of the Lich King bosses and purchasing some set pieces straight from the vendor with gold. Dropped tokens can be traded for set pieces via Dalaran tier vendors.
How to Get Warrior Tier 7.5? By purchasing from vendors and slaying Naxxramas/Obsidian Sanctum bosses.
How Many Set Pieces?  Helmet, Shoulders, Chest, Hands, and Pants
Warrior Tier 7.5 Transmog: [25-Man Drop Locations]
Note: Warriors have two different sets with the same exact look. Tier 7.5 warrior armor tokens can be used to purchase any of the set pieces.
Head: Crown of the Lost Protector [Kel’Thuzad] in Naxxramas
Chest: Breastplate of the Lost Protector [Gluth] in Naxxramas
Hands: Gauntlets of the Lost Protector [Sartharion] in The Obsidian Sanctum
Legs: Legplates of the Lost Protector [Purchase from Vendor] in Dalaran.
Shoulder/Leg Vendor (Alliance): Arcanist Ivrenne [37,55] in Dalaran.
Shoulder/Leg Vendor (Horde): Magistrix Lambriesse [65,23] in Dalaran.
Redeem Token Vendor (Both): Griselda Hunderland [46,28] in Dalaran.
Set Name: Valorous Dreadnaught Battlegear (hover for set bonuses)
Shoulder: Valorous Dreadnaught Shoulderplates
Chest: Valorous Dreadnaught Battleplate
Hands: Valorous Dreadnaught Gauntlets
Legs: Valorous Dreadnaught Legplates