Question, I have a TREK deck. First and second floor. Will the posts hold nails? And if they do, what kind. I would like to hand a large lantern that is secured by a metal hanging post that takes two of something. HELP

If I remember correctly, the trex posts are actually sleeves that fit over a 4x4.

I'd recommend screws long enough to go into the wood inside the sleeve. Maybe about 2 1/2"? Use stainless to avoid rust stains, and pre-drill the holes first.

There not sleeves but not totally solid either. As for your question though , yes they will hold nails and screws just fine, the post are hollow in the center but you should have at least an inch thick on the edges to drive a nail or screw. So your fine to do that