An Arcane Focus is a specialized item — an orb, a crystal, a rod, a specially constructed staff, a wand of wood, or some similar item — designed to channel the power of arcane spells. It is not in itself a magic item.
Subject to certain conditions, the Arcane Focus takes the place of a spellcaster component pouch, and the rules state that you may have one or the other. If the material component required by a spell is low value and not consumed by the spell itself, then the Arcane Focus is a perfect substitute.
The spellcaster must still have their hand free to hold and utilize the Focus, just as they would if they were using the material components.
In some ways, the Focus is better than a bag full of components that can get wet, lost, or stolen without too much fuss. However, lose or break your Arcane Focus, and you have effectively lost the equivalent of your magical bag of bits, which renders you both looking foolish and possibly a firefly short of a Light Spell.
It should be noted that if a spell consumes the material component or requires a material component with a listed gold piece value (i.e., it isn’t a commonly found item), then the spellcaster must provide that component. A focus will not work as a suitable substitute.
- An orb
- A crystal
- A specially constructed staff
- A wand-like length of wood
You can discuss the possibility of other items with your Dungeon Master to add a bit of unique flavor to your campaign.