This WoW set features the full Cryptstalker Armor transmog, which is the hunter tier 3 raid set. Cryptstalker was orginally added in vanilla patch 1.11.0, then removed with the Naxxaramas revamp during Wrath of the Lich King, and finally made available once again in Mists of Pandaria via the Black Market Auction House.
How to get hunter tier 3? By bidding for the pieces on the BMAH.
How many set pieces?  Helmet, Shoulders, Chest, Bracer, Hands, Belt, Pants, and Feet.
Hunter Tier 3 Transmog:
Head: Cryptstalker Headpiece by purchasing the helmet from the BMAH.
Chest: Cryptstalker Tunic by purchasing the chest from the BMAH.
Wrist: Cryptstalker Wristguards by purchasing the bracers from the BMAH.
Hands: Cryptstalker Handguards by purchasing the gloves from the BMAH.
Waist: Cryptstalker Girdle by purchasing the belt from the BMAH.
Legs: Cryptstalker Legguards by purchasing the pants from the BMAH.
Feet: Cryptstalker Boots by purchasing the boots from the BMAH.