Read from the World of Warcraft client build files.
How Deepfiend Shoulder Shells Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Deepfiend Shoulder Shells suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Transmog Sets
Deepfiend Shoulder Shells is part of the transmog set Khaz Algar Trophymaster's Mail Armor (Hunter, Shaman and Evoker only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 223396 (223391 to 223401) were usually added in the same batch as Deepfiend Shoulder Shells: the same quest line, zone, vendor or reward set.