The Gigas Chestplate is a high-ranked light armor in Final Fantasy XII that boosts the wearer's defense by 47 (Zodiac) or 38 (original), HP by 540, and—unusually for a light armor—Magick Power by 2. It can thus be a good armor for those who also use magick, such as for support healers.
The Gigas Chestplate is made in the bazaar set "Gigas Gear" by selling eight Prime Pelts (from some feline and canine enemies, e.g. Cerberus), seven Prime Tanned Hides (from a few enemies, e.g. Basilisk), and seven Dark Crystals (from numerous enemies, e.g. Tartarus).
In the updated Zodiac versions, the Gigas Chestplate is sold in Balfonheim Port after obtaining the Treaty-Blade. It is found in a treasure in Ridorana Cataract's Echoes from Time's Garden (75% chance to appear, 50% chance for gil, 50% chance the item treasure is the Gigas Chestplate without the Diamond Armlet equipped).
It is still the rare drop from Molen and is made in the bazaar set "Gigas Gear" with the same items as before.
The Gigas Chestplate is a high-ranked light armor, giving 47 or 38 defense depending on version, 540 HP, and 2 to Magick Power. In the original version where everyone can wear any equipment piece, the more expensive heavy armor, Dragon Mail, or the mystic armor Cleric's Robes, may be preferable purchases if the player can stretch their funds to them, 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 Gigas Chestplate boosts Magick Power as well, it falls short of what mystic armor give.
In the Zodiac versions, Machinist, Monk, Archer, and Shikari can equip the Gigas Chestplate, and so it is only useful to buy 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. Gigas Chestplate's magick boost could be useful for a combination that is using magick, but does not unlock mystic gear, such as Knight-Shikari etc used as a support healer.
To make it in the bazaar, the player can procure the items for it fairly easily after getting access to the deeper reaches of Feywood, and fight Cerberi, Tartari and Basilisks, which appear in numbers in certain areas there. Another way to get it is from a rare drop from the Rare Game Molen in the Zertinan Caverns.
Gigas is a popular term for races of giants in fantasy games. Gigas is a Greek word meaning "giant", originally used to describe the race of Gigantes in Greek mythology and is used in the scientific name, as the specific epithet, of hundreds of species of animals and dozens of plant species to denote their size.