I live in Arizona and play a lot of golf.  I like a full brimmed hat which offers good sun protection, but it also must be well vented to keep the head from getting soaking wet.  I also have a large head, 7-7/8 or 8  hat size.  XL hats are always too tight and uncomfortable.  This is the perfect hat-so good, I have just ordered a second one. I ordered it in triple XL and it fits perfectly. The crown is fully vented and so it is comfortable in even the hottest sun.