In Wrath of the Lich King it is item level 251 and requires level 80. In MoP Classic it is item level 251, requires level 80 and sells to vendors for 1c.
Read from the World of Warcraft client build files.
How Relentless Gladiator's Mail Helm Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Relentless Gladiator's Mail Helm suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Items Numbered Next to Relentless Gladiator's Mail Helm
Blizzard numbers items as they are created, so the named items next to ID 41020 (41014 to 41027) were usually added in the same batch as Relentless Gladiator's Mail Helm: the same quest line, zone, vendor or reward set.