Thanks. That's the (gonna show how stupid I am so brace yourself) upper half of the valve, the electrical/dry-side. I'm guessing the bulbous things are magnets that slide up & down inside the electric coils. Below that metal-plate is the coolant-side of the valve that have brass-seats. When closed no coolant flows through (into the cabin). To show how cheap Mercedes got the shaft attached to the brass seats is plastic instead of making the whole part out of brass. I guess some engineer figured out a way to save 10 cents times millions of valves in hopes he'd get a raise!