I have "EcoWeb", not Epiweb, although they are essentially the same. They are both nonwoven polyester matting about an inch thick. They DO NOT wick water, and only hold tiny droplets, so if used as a mounting material, you have to water the plants normally and regularly.
Hygrolon is another product from Mikael Karlbom (the Epiweb guy in Sweden). It is a roughly 1/8" thick, synthetic fabric that absorbs and holds water well. It does wick, but in my experience, not enough for a passive tray at the bottom to keep more than about 6" height moist. Of course, the ambient humidity will affect that. Many folks apply it over a structure made of EcoWeb or Epiweb, to provide the moisture over an airy substrate.
I think I may have a domestic source of something a bit better, but am still in the testing stage.