This WoW set features the full Cataclysm transmog, which is the shaman tier 5 raid set. Cataclysm is obtained by looting armor tokens from various Burning Crusade bosses. These tokens can be traded for set pieces via Shattrath City tier vendors.
How to Get Shaman Tier 5? By slaying Serpentshrine Cavern and The Eye (Tempest Keep) bosses.
Are There Multiple Tier 5 Transmogs For My Class? No, some classes do have multiple tier 5 sets (depending on their class trees), but every tier set variation features the same exact transmog look. For example, the paladin has a different set for retribution, holy, and protection, but all three sets share the same exact model and color variation. (Hunter, Mage, Rogue, and Warlock feature only one tier 5 set)
How Many Set Pieces?  Helmet, Shoulders, Chest, Hands, and Pants
Shaman Tier 5 Transmog: [Drop Locations]
Note: Shamans have three different sets with the same exact look. Tier 5 shaman armor tokens can be used to purchase any of the set pieces.
Head: Helm of the Vanquished Champion by slaying Lady Vashj in Serpentshrine Cavern.
Chest: Chestguard of the Vanquished Champion by slaying Kael’thas Sunstrider in The Eye.
Hands: Gloves of the Vanquished Champion by slaying Leotheras the Blind in Serpentshrine.
Legs: Leggings of the Vanquished Champion by slaying Karathress in Serpentshrine.
Tier 5 Set Vendors: [24,27] Kelara (Aldor) OR [44,91] Veynna Dawnstar (Scryer) | ~Shattrath City~
Set Name: Cataclysm Harness (hover for set bonuses)
Shoulder: Cataclysm Shoulderplates
Chest: Cataclysm Chestplate
Hands: Cataclysm Gauntlets
Legs: Cataclysm Legplates
Set Name: Cataclysm Raiment (hover for set bonuses)
Shoulder: Cataclysm Shoulderguards
Chest: Cataclysm Chestguard
Hands: Cataclysm Gloves
Legs: Cataclysm Legguards