HyperKewl vests provide hours of cooling relief. Simply submerse the entire vest in water for 1 - 3 minutes and wring out excess water and stay cooler and enjoy. Cooling vests are waterproof on the inside, yet hold and retain water on outside for 4-6 hours creating a cooling effect you won't believe. Inside is water repellant nylon to minimize wetness on the interior of the garment. An absolute MUST HAVE for Hot Weather Riding!