They're made almost 100% from the fiber of some yam plant (I think?). I buy/eat them all the time here!!! I can get them for 50 cents a pack. I probably go through 5 packs a week
. Good stuff! They're pretty much zero cal and the texture doesn't really bother me at all. I rinse them well and stir fry them.
At the Japanese grocery they're in the refrigerated section of produce. I don't know where they keep them in the US. I assume somewhere in a cold case.