External Strut mounted vane or yarn Angle of Attack indicator. Compared with the windscreen indicator here we see the angle of attack and yaw indicators split into to two units where they can be placed on strut and wing of a high wing aircraft to the left and right of the pilot outside of the slip stream. In a low wing aircraft the sensor might be integrated with a strake type anti stall vortex generator.
Vane Angle of Attack made of L metal indicator. This angle attack indicator or wind vane is made by cutting away materiel . This is a very inexpensive way to make a wind vane without tooling.