Tier 4 is the first tier of raiding gear in The Burning Crusade. The tokens drop in the three starter raid instances; Karazhan, Magtheridon and Gruul's Lair, and consist of a head piece, chest, shoulders, legs and gloves.
Under each picture I have linked matching belt and boots to help complete the set.
For each class that can have different roles the sets have different names, but they all look the same so it does not matter too much which item set you pick for transmogging.