Just the one close up pic, with the cap in place, it appeared to be built on to the swing possibly...

It gives me ideas , that's all. (and it was nicely executed)

The small section of 9.5mm , or what ever size you use to put the quartz arm and seals inside. (sits on the side of the dome) that clear tube , we always referred to that tube with two open ends as the "noodle"