The Power Vest is a mid to high-ranked light armor in Final Fantasy XII that boosts the wearer's defense by 41 (Zodiac) or 34 (original), HP by 400, and—unusually for a light armor—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.
In the original PlayStation 2 versions, the Power Vest is sold for 8,100 gil in Archades and Balfonheim Port. It is found as a treasure in Draklor Laboratory's 66th Floor - Room 6613 East (room in the northeastern corner; 70% chance to appear, but is always the Power Vest without the Diamond Armlet equipped). This is an unrevisitable location, and so the player can't return for it should they miss it.
It is also made in the bazaar in the "Emboldening Arms" set by selling six Quality Pelts (from various enemies, e.g. Coeurls), four Tanned Giantskins (from giant-type enemies, e.g. Slaven Wilder), and three Fire Crystals (from various enemies, e.g. Scythe Mantis).
In the updated Zodiac versions, the Power Vest is sold for 8,100 gil in Balfonheim Port. It is found in a treasure in Feywood's Ice Field of Clearsight (75% chance to appear, 50% chance for gil, 50% chance the item treasure is the Power Vest without the Diamond Armlet equipped), and the Necrohol of Nabudis's Hall of Slumbering Might (30% chance to appear, 30% chance for gil, 50% chance the item treasure is the Power Vest without the Diamond Armlet equipped).
It is still rarely stolen from the Tartarus and made in the bazaar set "Emboldening Arms" with the same items as before.
The Power Vest is a mid to high-ranked light armor, giving 41 or 34 defense depending on version, 400 HP, and 2 to Strength. In the original version where everyone can wear any equipment piece, the more expensive heavy armor, Platinum Armor, or the mystic armor Jade Gown, 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 Power Vest boosts Strength a little bit, heavy armor pieces give more.
In the Zodiac versions, Machinist, Monk, Archer, and Shikari can equip the Power Vest, 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. For a job combination that doesn't unlock any heavy armor, the Power Vest may be a good armor to equip for the small Strength boost it provides, unless the character wields a gun.
Power Vest is a good light armor that is potentially available through the bazaar much earlier than it is available through the shops. The items needed to make it are not especially rare, either, and it comes with a good complement piece, the Chakra Band, as well. The player can skip many light armor sets if they get the Power Vest and Chakra Band from the bazaar early.
While localized as a vest, a tatsuki is a traditional Japanese accoutrement for martial arts, especially for samurai. Slung around the back of the wearer, the crossed arrangement of the cloth allowed long and hanging sleeves to be pulled and tied back for greater mobility and clearing them when wielding weapons such as spears and swords, as the sleeves would catch through the moving pommel and handle without it.