For those looking for something to help cool them during the summer months, there are a couple of companies that sell cooling towels. These are basically made out of the material used for shammies, those things used to dry your car after you wash them.
I know it sounds weird but THEY WORK!! I was first introduced to them in Afghanistan when we received a couple in a care package. I was skeptical at first but after the first day using them, I am a believer.
You soak them and wrap around your neck and they help keep you cool. If they start to dry out then re-soak.
I still use mine to help during the hot Texas summer months and they help a lot.
They can be found at the big home improvement stores or other places.