Question about Hats

Okay, so I've gotten to the point where I get distracted with small (and sometimes impossible) details. For example, there is this guy named Wilbur and he has a very characteristic hat that looks like this:

But I can't for the love of God *inhaling deeply* figure out what this kind of hat is called. Anyone who knows the name in either Swedish or English? It would be a great help.

Thanks, A.