It is damn near impossible to tell unless you hav something to compare it to. They apear to be either stainless or titanium... hard to tell by the pics... how much do they weigh? titanium will be WAY ;ighter than stainless.
The D&D will pretty much fit anything with the same diameter "s" bend pipe to connect it to.
i put a magnet to it and no sticking so i figured it was titanium plus its superlight but i dont see any d7d pipes with the connection springs at the joints
let me know cuz it could help i'm going to take measurements today