Amulet of Trithereon

While holding this rod, you gain a +1 bonus to spell attack rolls and to the saving throw DCs of your spells.

Also, as a bonus action, you may take 2d10 damage and expend a charge to regain 1d4-1 (minimum 1) expended spell slots.

Notes: Bonus: Spell Save DC, Bonus: Spell Attacks, long rest