Amulet of the Devout

From Tasha's Cauldron of Everything, page 119.

Description
Wondrous item, uncommon (+1), rare (+2), very rare (+3) (requires attunement by a cleric or paladin)

This amulet bears the symbol of a deity inlaid with precious stones or metals. While you wear the holy symbol, you gain a bonus to spell attack rolls and the saving throw DCs of your spells. The bonus is determined by the amulet's rarity.

While you wear this amulet, you can use your Channel Divinity feature without expending one of the feature's uses. Once this property is used, it can't be used again until the next dawn.