The directionals are a quest item used in the One Small Favour quest. They are obtained by climbing onto the roof of Phantuwti's house in Seers' Village and removing the broken vane parts. The directionals must then be repaired using an iron bar at an anvil and returned to the top of the house along with the repaired weathervane pillar and ornament.
Once the three repaired vane parts have been returned to their position the player can speak to Phantewti in order to complete the next step in the quest.