There were two sets available for this one, one for healing and one for DPS. The helm has a purple glow around it.
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