Weird thing in the MotoRad 206-180 Box

Thanks guys. I warmed up the stat and it started to open around 165 and was fully open at 180, so it seems to be functional. Old one was stuck open so I was heating up very slow and running too cool. I looked back at the listing and determined that it doesn't come with a gasket, so I picked up a Felpro from O'Reilly on the way home. I'll put a super thin layer of rtv on the gasket and get it all together this weekend.