A wand is an item for storing many (up to 50) copies of a single spell. Their usage is often restricted to the classes that can cast that spell normally. Wands cannot be equipped, but are instead activated from a character's inventory. They can also be assigned to a quickslot for faster access. When a wand's remaining charges are reduced below the number needed for the spell, the item is destroyed.
Wands can be created with the craft wand feat, which gives a wand usable only by arcane or divine casters (matching the class used to cast the spell that created the wand). Such wands are often used to augment a character's spell slots, either by providing a spell that is used often (more times between rests than the character has available spell slots), or one that is used seldom (so seldom that it is not worth reserving a spell slot for that spell on the off chance it will be useful).