The Dueling Mask is the ultimate light armor headgear in Final Fantasy XII that boosts the wearer's magickal defense by 55 (Zodiac) or 45 (original), HP by 800, and—unusually for a light armor headgear—Strength by 2. It can thus be a good headgear for those who use melee attacks, especially for some License Boards in the Zodiac versions that can't unlock heavy armor. The preceding light armor hat, Renewing Morion, provides Auto-Regen, and thus it is up for the player's consideration which one would suit their party better.
In the original PlayStation 2 versions, the Dueling Mask can be found in Pharos . The player must first destroy green Brainpans in the The First Ascent Wellspring Ravel 3rd Flight to build bridges. There is a treasure at 35F with a 70% chance to spawn, but to obtain it, the player must return to previous floors and defeat three red Deidars to create a red bridge to the chest. The chest has a 100% chance of containing a Dueling Mask (with or without the Diamond Armlet). Once claimed, the chest will never respawn.
Subterra Abyssal-South also has a 50% chance to spawn a chest that guarantees a Dueling Mask if the Diamond Armlet is not equipped. Once claimed, the chest will never respawn.
In the updated Zodiac versions, the Dueling Mask can't be bought but sells for 10,000 gil. It is found in Henne Mines' Phase 2 Dig (always appears), and Cerobi Steppe's Crossfield (20% chance to appear, 80% chance for gil, 5% chance the item treasure is the Dueling Mask with the Diamond Armlet equipped). To get to Phase 2 Dig, the player must collect 10 Espers and talk to the geomancer in Jahara.
The Dueling Mask is also obtained through the Hunt Club sidequest on the Phon Coast by giving Blok 20 Rare Game trophies to make the Dueling Mask purchasable from the Shifty-Eyed Merchant nearby for 117,000 gil.
The Dueling Mask is the light armor hat with the best stats, giving 55 or 45 magick resist depending on version, 800 HP, and 2 to Strength. In the original version where everyone can wear any equipment piece, the top tier heavy armor helms (Genji Helm, Magepower Shishak, and Grand Helm), or the top tier mystic hats (Black Mask, White Mask, Golden Skullcap and Circlet), may be preferable to equip over light armor gear, as the HP boost from light armor is not usually worth prioritizing over heavy armor that boosts Strength for physical attackers, or mystic armor that boosts Magick Power for spellcasters. Though the Dueling Mask boosts Strength a little bit, heavy armor pieces give much more.
In the Zodiac versions, Machinist, Monk, Archer, and Shikari can equip the Dueling Mask, and so it is only useful to look for if the player has chosen these License Boards for their party. In The Zodiac Age, after fighting Belias, the player can choose two License Boards per party member, and so more party members can choose from the potentially more useful heavy and mystic armor sets. For a job combination that doesn't unlock any heavy armor, the Dueling Mask may be a good headgear to equip for the small Strength boost it provides (although meaningless for a gun-wielding Machinist), as its other stats are still good.
The 800 HP that the Dueling Mask provides is a great boost, especially when doubled under Bubble. With the best light armor gear and Bubble, the player can exceed the 9999 HP cap shown in the user interface.