If this charm is kept on your person it will keep you fed and protect you from drowning. Keep in mind that it can wear out and will be destroyed if overused.
The Charm of Vigor may be enchanted with Self-Repair I.
The charm, if kept in your inventory will "feed" you when your hunger bar drops, denoted by a quick eating sound. The charm will also refill your air meter once it reaches five remaining bubbles. The item loses durability when performing each of these functions.