Metamagic, Elemental

Each elemental metamagic rod is built with the power to control and transform a specific energy type (acid, cold, electricity, or fire). The wielder can cast up to three spells per day that deal damage of the rod's energy type instead of the spell's normal damage type, as though using the Elemental Spell feat. For example, an elemental metamagic rod (cold) always makes spells deal cold damage.