Source: Tasha's Cauldron of Everything

Wondrous item, rare (requires attunement by a wizard)

The pages of this book are bound in fiend hide, and its cover is embossed with a diagram of the Great Wheel of the multiverse. When found, the book contains the following spells: Banishment , Find Familiar , Gate , Magic Circle , Planar Binding , and Summon Elemental . It functions as a spellbook for you.

While you are holding the book, you can use it as a spellcasting focus for your wizard spells.

The book has 3 charges, and it regains 1d3 expended charges daily at dawn. You can use the charges in the following ways while holding it:

• If you spend 1 minute studying the book, you can expend 1 charge to replace one of your prepared wizard spells with a different spell in the book. The new spell must be of the conjuration school.
• When you cast a conjuration spell that summons or creates one creature, you can expend 1 charge to grant that creature advantage on attack rolls for 1 minute.