I recently purchased a new hat. It's an Allessandra, and made by Borsalino, sold by a store in New York, and it arrived in the mail.
The most interesting part is the size. The sticker basically reads "62 7-1/2 UK 7-5/8 USA 7-3/4". That's where the fun begins. The hat is measured in centimeters, and, sizes are increments of centimeters. Thus, this has is a "62" as it is 62 centimeters on this inside. In the US, for easier reading, the centimeters are counted in groups of eight. As such, 62 / 8 = 7-3/4. Though, strangely enough, in the US this size is sometimes called a 63. Go figure. Why the UK goes one lower, and the standard (Italian?) size is lower than that, is a mystery to me. Well, at least i think that's how it works. I'd measure it myself, by my tape measure isn't so flexible. And, it's oval shaped.
On top of that is paying for the hat, and hats are not cheap, at least not the type that i buy. I paid over one-hundred dollars for it. Well, it should last a number of years, so it isn't that bad.
Considering i wear a large hat, i love getting other people to try it on, as it usually falls down to their ears. Though, my brother-in-law, wears a size up from me.