Primal Gladiator's Mail Helm is part of the transmog set Primal Gladiator's Ringmail Armor (Shaman only), which the Appearances collection lists in 2 versions. The other 16 pieces:
Items Numbered Next to Primal Gladiator's Mail Helm
Blizzard numbers items as they are created, so the named items next to ID 115944 (115939 to 115949) were usually added in the same batch as Primal Gladiator's Mail Helm: the same quest line, zone, vendor or reward set.