Dangerden fillports are copper/brass (outer bit) and aluminum (center) for great corrosion fun!
lol, if used as a drain valve at the bottom of the case where coolant is always circulating over it i can agree - but when the drain valve is at the top of a system normally, and about 99% of the time there is coolant in the loop, corrosion is less likely to happen right? the coolant is not making contact with the aluminum parts of the tline if its the highest component in the loop, when acting as a res i think...
just my thoughts im really wanting a tline now, connected to one of petras resevoir (connected via the top, so i can fill easily from outside my case, yet drain easy by flipping my case upside-down).