Any good western store will be able to help.
One of the largest selections I've ever seen is at Bear Creek Western Store about an hour above New Orleans in Montpelier, LA. Open 7 days a week, very knowledgeable staff and very good prices (actually better than most of the bigger "chain" stores. I've been dealing with them for 30 plus years.
https://m.facebook.com/pages/categor...2129939155793/
If I'm not mistaken a 10x is pure beaver felt. That's what my Resistol is