Staff

A gnarled or polished staff of wood, bone, or more exotic materials like crystal. Such implements are frequently used by spellcasters to hone their arcane focus.

Spellcasting Focus. An arcane focus is a special item designed to channel the power of arcane spells. A sorcerer, warlock, or wizard can use such an item as a spellcasting focus, using it in place of any material component which does not list a cost.