Poison Spyder aluminum tube.
I agree, and just installed mine. They are great! PSC is the only tube fenders (That I'm aware of) that include additional bracing. This bracing essentially ties the outer sheet metal to the inner structure. They also have engineered the reuse of the stock liner (If using it is important to you, it was for me).
The reason I had to replace mine was due to damage that my stock flares caused when a branch got wrapped up in the front tire. My fender got bent and creased before the flare broke away. (actually before I even knew it was happening)
So while I read comments all the time about how they will "Just fold up" I have experienced instances where they will cause damage too. I think the trick it the stock trim mod. By removing the inner liner and some bracing you make them more complaint. In my case they were in stock form.
Whatever you do I would avoid tube fenders that simply mount to the thin sheet metal. They will likely do more harm than good when things get rough.
Just my :twocents: