Just dug my kit out so I could check the label. I'm taking the kit with me to my retreat next month, love that it's all cut when it arrives!
The label looks like what is put in clothing, woven of nylon would be my guess.
Here's one I found
http://www.arrowtextiles.com/docs/sm...s-accepted.php Made me laugh, this is their link for "small orders," which would cost a minimum of $300!!