Ioun Stone of Concentration

Wondrous Item, requires attunement by a spellcaster.

RPG Datasheet

While attuned to this item, it hovers in the air in a slow orbit around your head and shoulders. You may instead cause it to orbit your spellcasting focus if you use one. While floating, the stone has AC 24, 10 hp, and resistance to all damage types.

• While attuned to this item, if you attempt to cast a spell that requires concentration while already concentrating on an existing spell, you can maintain concentration on both spells simultaneously. You must spend a standard action each subsequent round on maintaining this concentration, or lose concentration for both spells.
• At the end of each turn where you have two spells you are concentrating on, you must make a CON saving throw (DC equals 10 + the number of complete rounds you’ve been concentrating on two spells). On a failure, you lose concentration for both spells. You can drop concentration on one of your spells during your turn as a free action to avoid this saving throw.
• Any time you would be forced to make a CON saving throw to maintain concentration due to taking damage, the DC equals 10 + both spells’ levels combined, or half the damage you take, whichever number is higher. On a failure, you lose concentration on both spells.
• At any time when you fail a concentration check while maintaining two concentration spells, the stone falls lifeless to the ground and cannot be used again until the next dawn.