[Fot] Cool Shirts and Power Vented Helmets

[Scott Janzen]

Anyone have any experience with these? after just spending a hot, sunny
weekend at the track in a dark green coupe, I am very interested in the power
vented helmets hooked up to cold air.  I think if my head is cool the rest of
me will be comfortable, and I don't like the idea of the water shirt under a
nomex suit.  What's in those "coolers" - is it an air to water heat exchanger,
or just air getting drawn over ice water?  Baffles? Could I make one?
Feedback much appreciated!