Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Deepcaller's Clasp Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Deepcaller's Clasp suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Transmog Sets
Deepcaller's Clasp is part of the transmog set Queen's Guard Scalemail (Hunter, Shaman and Evoker only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 169927 (169921 to 169932) were usually added in the same batch as Deepcaller's Clasp: the same quest line, zone, vendor or reward set.