What are the sizes of the large. I wear a 7 1/2, so would I need the large or regular?
Doug my head circumference is about 23 inches and my size L fits fine.
Definitely a large. I measure a 7 3/8 and got the regular. It is very tight. This is not my favorite hat, but it is very light for the weight, so I keep it in my backpack. Check out the youtube video for looks - it is not your typical beanie, but is intended to keep some airspace above your noggin.
Visit the Mountain Hardwear website, find the Zerna Beanie and click the "Size Chart" tab. According to the table presented there, a 7.5 is right between regular and large. So, you need to guess or get both and return one of them.