Thermoquad Part Question

I didn’t wanna hijack the other TQ thread with my own questions. I have a 9245 that I’ve started rebuilding. I have the majority of it apart.
I’m trying to figure out what that last part is though. It’s attached at the rear of the carb to the top plate, next to the spot where the fuel line mounts. Any ideas as to what it is? The book I’m using as a manual doesn’t have it. (And sorry for the picture sizes, I took the pics with my phone)

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Thermoquad Part Question
Author: Lightning II