Found in Ornate Chest worn for protection every piece has the same prefixes and suffixes, but some has their own unique ones making each one of them different from the other.
Vault Armor can be modified using Artisan Station with a combination of Focus to add individual modifiers.
Vault Chestplate
Vault chestplate has a unique modifier adds +1 to a random ability while also it's the only armour that has block chance as an implicit.
Vault Leggings
Vault Leggings has a unique modifier adds +1 to a random ability similar to vault chestplate except it does not have block chance as an implicit.
Vault Helmet
Vault Helmet is the only armour piece with lucky hit chance as an implicit and Area Of Effect as a suffix.
Vault Boots
Vault Boots being the only armor piece that has movement speed % as an implicit making you run faster.