The Survival Vest is a mid-ranked light armor in Final Fantasy XII that boosts the wearer's defense by 17 (Zodiac) or 16 (original), HP by 140, and Vitality by 5. It can thus be a good armor for those who use weapons that take the wielder's Vitality stat into account: axes and hammers and hand-bombs. However, a helm that boosts Strength likely has a bigger impact on the damage dealt, and in the Zodiac versions, the Foebreaker can't natively equip light armor.
In the original PlayStation 2 versions, the Survival Vest is sold for 1,900 gil in Rabanastre after defeating Belias, and in Jahara. It is found as a treasure in the Zertinan Caverns' The Balamka Fault (60% chance to appear, 60% chance for gil, 50% chance the item treasure is the Survival Vest without the Diamond Armlet equipped ) and the Ozmone Plain's Dagan Flats (west; 50% chance to appear, 40% chance for gil, 50% chance the item treasure is the Survival Vest without the Diamond Armlet equipped). It is rarely stolen from the Iguion.
In the updated Zodiac versions, the Survival Vest is sold for 1,900 gil in Jahara and Mt Bur-Omisace. It is found in a treasure in the rainy Giza Plains' Tracks of the Beast (80% chance to appear, 35% chance for gil, 50% chance the item treasure is the Survival Vest without the Diamond Armlet equipped), as well as in the Trial Mode Stage 52 with the Diamond Armlet equipped.
The Survival Vest is a mid ranked light armor, giving 16 or 17 defense depending on version, 140 HP, and 5 Vitality. It is useful to equip over any inferior equipment the party may have. However, in the original version where everyone can wear any equipment piece, the more expensive heavy armor, Golden Armor, or the mystic armor Traveler's Vestment, 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 Survival Vest boosts Vitality, its effect is small, and even those whose weapons take the wielder's Vitality stat into account benefit more from the Strength-boosting heavy armor.
Vitality affects the duration of statuses. Negative statuses are shortened while positive statuses are lengthened. Higher Vitality decreases the enemies' success rate of landing negative statuses on the character.
In the Zodiac versions, Machinist, Monk, Archer, and Shikari can equip the Survival 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. None of these jobs' base weapons also benefit from the Vitality boost the Brigandine offers, though the Machinist can access mid to late-game hand-bombs by unlocking Shemhazai and Zeromus; the Machinist will likely do more damage with guns, however, and these late-game Espers are more useful when assigned to other boards.