There were three different sets of Shaman Tier 4, one for resto, one for elemental and one for enhance.
This set is purchased with tokens that dropped off bosses in various raids.
Helm token – Prince Malchezaar in Karazhan
Gloves token – The Curator in Karazhan
Chest token – Magtheridon in Magtheridon’s Lair
Pants token – Gruul the Dragonkiller in Gruul’s Lair
Shoulder token – High King Maulgar