On Black Diamond Z Poles

I'm still reading The Return of the King. It's fascinating to see the characters move around the land. I don't recall noticing the first two times I read it just how fascinated with landscapes that Tolkien is. There are many passages of wild, amazing geographical features that the characters have to defeat even without using Black Diamond Z-Poles. Of course, what they lack modern technology and fabrics, they make up with Elvish magic. There's a technological assumption they know metal working quite well. I guess that is consistent with the basically medieval life style.