Yvelda's orb acts as an arcane focus, druidic focus or holy symbol.

Spell cast using Yvelda's orb as a spell focus get +1 to spell attack roll and save dc.

Once per day, you may cast one of your level 1 spells without using a spell slot.

(From The Mystery of Witchhaven book from Obivious mimic.)

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