A smoke grenade fills all squares within 10' of the target square with concealing smoke for two rounds. Grenades affect any creature within 5 ft. of the target square (make one attack roll and apply it to each creature). An empty square is typically DEFENSE 10 to hit, and the range increment of a grenade is 3 squares (15'); alternatively, a grenade can be inserted into a grenade launcher and use the launcher's range increment.