It’s made of 5052 aircraft-grade aluminum and comes in at 11 lbs. To give you an idea of the shelf positioning, measure 10" down from the top center of the headliner edge. That is where the shelf will rest on top of the mounting hardware.
We recommend keeping the load under 50 lbs.
It doesn’t include a foam piece as this clashes with the aesthetic. Some users use a pipe-foam or similar insulation to wrap the edge. But to be honest, we’ve found that after a couple of good knocks, you tend to be conditioned to duck when entering the cabin.
We have one in our van and so far, so good! It does its job of keeping our stuff in place, no flex noise nor vibrations.
The center channel is for structural support along the width of the shelf.