In 1985 Sandra Steele marketed the first practical, modestly priced cooling vest that really worked, the six pocket SteeleVest. The vest has a shell fabric of FR Certified Indura cotton, and 6 insulated cooling pockets (3 horizontal on front of vest and 3 horizontal back pockets). The frozen gel Thermo-strip cooling medium is composed of food-grade and organic materials that combined have a neutral Ph and are completely nontoxic and nonflammable. In most applications, Steele Thermo-strips are more effective than other gel packs because of their virtually nonexistent expansion rate and unique, self-insulating ability. Also, independent testing (report available) prove that Steele Thermo-strips offer 30% more net torso cooling as compared to phase change style cooling packs. The cooling effectiveness of the SteeleVest & Thermo-strips has been well documented in over 25 human subject tests and evaluations performed by various government agencies over the years. The SteeleVest fully loaded with gel Thermo-strips weighs between 8 - 12 pounds and will keep your body core temperature down for 3-4 hours before needing to exchange the Thermo-strips.