Source: The Book of Many Things

Wondrous Item, varies

While you’re wearing these cloth wraps, your unarmed strikes are considered magical for the purpose of overcoming immunity and resistance to nonmagical attacks and damage, and you gain a bonus to the attack and damage rolls of your unarmed strikes, determined by the wraps’ rarity.

Rarity Bonus
Uncommon +1
Rare +2
Very Rare +3