I dunno, 8lbs for the heavy-duty model (rated for 2.5 hours at 125 degrees ambient) seems like a small price to pay to travel both safely and more comfortably. From what my buddy was saying, the closer these are worn to the skin the more effective they are, so Im thinking Tshirt > Cooling Vest > Jacket should work OK.
By the way, theyve got lightweight ones that get down to the 4-5lb range.
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