The dwarf-masks were helmets of great crafting made in the First Age by the Dwarves of the Blue Mountains. These helmets had face plates which could be lowered over the face as a mask, and through this the fire of dragons might be withstood.
One such helm was the Dragon-helm of Dor-lómin, crafted by the smith Telchar for the Dwarf King of Belegost, Azaghâl. This he wore at the Battle of Unnumbered Tears where he fought Glaurung, Father of Dragons. Túrin Mormegil was gifted a dwarf-helm during his time in Nargothrond; and before this was the rightful heir to the Dragon Helm of Dor-lómin.