Accessory runes are runes that provide enhancements or abilities to mundane clothing, items, shields, and vehicles. Accessory runes must be physically applied to items through a special process to convey their effects, like all runes. You can apply an accessory rune to any mundane item that meets the criteria in the accessory rune's Usage entry. If allowed by the Usage entry, you can even apply an accessory rune to a magic item that doesn't have the invested trait, such as a shield. When you inscribe an item with an accessory rune, it gains the invested trait, requiring you to invest the item to gain its magical benefits. An item that already has the invested trait can never have an accessory rune inscribed on it.