I'll find out what it's called but I got it from wal greens, it is a white cloth like medical tape, the kind you tape your fingers together with.
I just trimmed the edges off and after taping it all up I used acrylic paint to color them. I use acrylic paint for all of the weathering as well,
I used scissors for the holes in the cloth but the tattered edges were done by burning the cloth with matches.