The Darrin vents open and close manually at each vent. Not all the Darrin vents had the eyelet on the vent lever. Some had just a straight arm with a small rubber ball on the end of the lever. Another running change during production. My guess would be early production was eyelet end, and later production would be the rubber ball end. My Darrin is late production #357, and has the rubber ball end vent levers.