Read from the World of Warcraft client build files.
How Primal Gladiator's Copperskin Helm Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear.
Transmog Sets
Primal Gladiator's Copperskin Helm is part of the transmog set Primal Gladiator's Ironskin Armor (Monk only), which the Appearances collection lists in 2 versions. The other 13 pieces:
Items Numbered Next to Primal Gladiator's Copperskin Helm
Blizzard numbers items as they are created, so the named items next to ID 115888 (115883 to 115893) were usually added in the same batch as Primal Gladiator's Copperskin Helm: the same quest line, zone, vendor or reward set.