I'm a chauffeur, and I was looking for a cap that would be suitable to wear with my black suit, keep my head warm on chilly nights, and be easy to store and maintain. This checks off all 3 boxes quite nicely.I measured my head at 22", so I ordered the medium. It arrived very quickly and I tried it on. It was a bit snug, but it did fit, however, after wearing it around my apartment for a bit, I decided to do some on-line checking (which I probably should have done first), and the general rule for these types of hats seems to be that it's better to get it a bit too large rather than a bit too small, because they can actually shrink a tiny bit over time, and if it's too tight, it can cause headaches.The rule of thumb is that it should stay put on your head when bending over, but should still be comfortable to wear (not tight), and that if it's a tiny bit too large at first, it's easy to place a bit of felt in the headband to "size" it down, which can then be removed later on if need be. It won't be tight enough to keep it from being blown off in the wind. That would be too tight.Anyway, I asked for an exchange for the next larger size and they shipped it out the next day, while issuing me a pre-paid return label for the cap I had, which I sent back that day. The entire process only took a few days and didn't cost me anything.The new LARGE Driver's Cap fits perfectly and looks wonderful, just exactly what I was hoping for. I like the soft interior lining, how nicely it fits, and the way it looks with my black suit.. It's top quality all the way.Thanks Headchange USA, not only for the wonderfully crafted and elegantly stylish cap, but for making the exchange process so quick and easy. Highly recommended.