I was VERY happy to look underneath today and find that they were heavy duty molded plastic rather than metal under the outer shell. Before I looked, I was envisioning a rusty mess years down the road. But this is good news...they'll last forever with a little care. By the way, I'm almost 200 lbs and they hold my full weight without budging or bending one bit. I love it

 

I'm almost 200lbs too (275), they are as solid as can be. I am happy with them too.