Headmaster’s Ring

Very Rare Wondrous Item
Requires attunement by a Wizard

Arcanist’s Library. As an action you can magically store one book inside an extradimensional space tied to this ring. You can store up to 30 books in the extradimensional space. You can use another action to retrieve one of the books from this space.
Teacher’s Patience. While wearing this ring you gain a +2 bonus to Concentration checks.
Magical Mentor. While wearing this ring you can spend 10 minutes talking to a group of up to 20 creatures. At the end of the 10 minutes roll a Charisma check (DC 10). On a success all creatures that were paying attention gain a bonus to their Intelligence score equal to half your Intelligence modifier (rounded up). This bonus lasts for 12 hours. You can use this feature once per long rest.