I live in Arizona, where it's very sunny 99% of the time.  I commute to work regularly, and I'm a bit too short -- so the windshield visor doesn't do much to block the sun's rays from my eyes.  That's where this long billed baseball cap helps.  And it does a great job.  The cap is all cotton -- very comfortable to wear for long spans of time.  The size is adjustable using a small brass clasp on the back (and to the side).  Fits my big noggin.
Buy this, I'm sure you'll like it.