They are just brass rods telescoped together so they move when the wings move. Nothing special . I used some electrical connectors as the main support with the hole and bent some brass rod through two 180 degrees and put them through the holes.
They aren't super detailed but strong enough to hold the pistons in place and let ti all rotate. Once you remove the insulation it leaves a nice spigot which you can glue into where ever you drilled the hole. I find it works ok for a quick build. Detail the ends to make them look a bit better. Cheap and cheerful for the hasbro