Action: Pulling the string to break the seal and activate the reaction in the arrowhead is a move action.
Benefit: You gain a +4 bonus on attack rolls when firing a lodestone arrow at a target wearing a significant amount of metal armor (at least chain mail or a metal shield) or made of metal. The increased magnetism fades 1 round after you activate it, after which time it is a normal arrow.
Special: In areas with a lot of magnetic metal, the attack bonus may drop to 0 or even become a penalty as competing sources steer the arrow away from your intended target.
Drawback: The magnetized arrow only deals half damage.
Source Elves of Golarion