A custom hat has to do with felting. Felting is a process, not a material – that’s why we call it “felted fur”. Felting is a heating under moisture and pressure that makes the individual hairs twist and angulate around each other in every direction imaginable. That’s why the beaver hair (which is much smaller) felts much tighter and holds stronger. Of course, beaver fur is a water repellent to begin with. Beaver fur is the most sought after when purchasing quality hats the hat making.