This WoW set features the full Heroes’ Cryptstalker transmog, which is the hunter tier 7 (10-man) raid set. Cryptstalker 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 Hunter Tier 7? By purchasing from Dalaran vendors and slaying Naxxramas bosses.
How Many Set Pieces?  Helmet, Shoulders, Chest, Hands, and Pants
Hunter Tier 7 Transmog: [10-Man Drop Locations]
Head: Helm of the Lost Protector [Kel’Thuzad] in Naxxramas
Chest: Chestguard of the Lost Protector [Purchase from Vendor] in Dalaran.
Hands: Gloves of the Lost Protector [Purchase from Vendor] in Dalaran.
Legs: Leggings of the Lost Protector [Thaddius – Gluth] in Naxxramas.
Chest/Hand Vendor (Alliance): Arcanist Ivrenne [37,55] in Dalaran.
Chest/Hand Vendor (Horde): Magistrix Lambriesse [65,23] in Dalaran.
Redeem Token Vendor (Both): Bragund Brightlink [51,72] in Dalaran.