2024 rules reference for Wand of Fireballs.
Wand
This wand has 7 charges. While holding it, you can expend no more than 3 charges to cast Fireball (save DC 15) from it. For 1 charge, you cast the level 3 version of the spell. You can increase the spell's level by 1 for each additional charge you expend.
Regaining Charges. The wand regains 1d6 + 1 expended charges daily at dawn. If you expendthe wand's last charge, roll 1d20. On a 1, the wand crumbles into ashes and is destroyed.
Spellcaster