TexasCHLforum.com

I have worn a felt hat year around all my life. A custom hat maker in Fort Davis where I had some of my hats made told me this about hats. X designations on the hat originally meant how much rabbit fur was in the blend to make a hat stay together due to the velcro type attributes of the fur. It takes at least 5% rabbit fur to make it stay together and this constituted a 20x hat, any more rabbit fur would be a lesser X number. Any more X designation than 20 on a hat (such as 100X) is meant to reflect how much stoning or smoothing of the surface was done. Still the same makeup of a 20X hat but smoother surface of hat as number of X's goes up.
The materials in the hat are still the same and price is higher due to stoning but it is not a better grade hat. For more X's than 20 you just pay more for stoning and it does not constitute a better hat.