The ones I've seen are like a flak jacket, but instead of armor the compartments are filled with a jell like substance. They are placed in a freezer overnight and give you, maybe, 3 - 4 hours of cool. This means you would have to have 2 and you would have to have some way to keep the second one frozen. There is a HVAC company on my route that uses them to do attic work in the summer; they felt real good when I tried one on, but they are in the $250 - $300 range, and I think you would need 2. Google cooling vests, or look through a safety catalog from one of your industrial consignees.