If the factory doesn't supply it, then finding one that fits a particular knife means going shopping either locally or online. Since you don't say what model of knife you're talking about
hard to say either way. I used Bing/Google to do a seach and found all sorts of places/people offering that material in sheaths. The stuff is cheap enough and easy enough to form; there are plenty of tutorials around on making kydex sheaths. Most knifemaker catalogs supply everything required. Wouldn't be hard to make your own if you don't want to pay the price of others doing it.
