My head measures roughly 21 inches or 55 centimeters. The proper size for this is 6 - 7/8 which is the size I purchased (there was only 1 left). The hat didn't fit snug so I purchased "Hat Size Tape Reducer Hat Sizer Insert Foam Reducing Tape Roll self Adhesive" with which the hat fits well (good adhesive). However, purchasing the hat a size down (6 - 3/4) and then using steam and/or a hat stretcher would have been preferable. Unfortunately, they did not have any more that are 6 - 3/4, or else I would have mailed it in as to exchange it for the proper size.

I am fond of this hat. I also purchased an adjustable silver hat band with buckle, for it, which looks totally awesome (I just need to stitch it on using a needle and thread).

I let my wife pick out a Gaucho hat that she would like. This was the only Gaucho one with a drawstring (high winds a regularity here).
She loves it - It looks great - and the fit was as expected.
Regular ground delivery was extremely fast.
Extremely pleased.