Hydrate by D'Addario is the ultimate treatment to restore the character of unfinished fingerboards on all stringed instruments. Hydrate's unique formula of oils and cleaners removes dirt and grime while restoring moisture to the fretboard, preventing cracks and other damage that can happen when a fingerboard becomes dry. Hydrate Leaves the fretboard feeling silky smooth for an improved playing experience. For dark, unfinished woods only.