ECTO 1A Dish antennae HELP

Anyone have a clue what the black “honeycomb mesh” material is that makes up the cross on the roof antennae dish? I have been scouring all over this site and the interwebs to no avail. Thanks in advance!

As far as I can tell it’s just “perforated sheet metal” with circular holes in a “staggered” pattern. Not sure of the holes’ diameter.