Fly Racing Cooling Vest (2023) Materials: Polymer embedded fabric holds the water and keeps you cool as the water evaporates. Remains hydrated for several hours. Features: HYPERKEWL PLUS evaporative cooling system helps keep you cool even through the hottest summer ride. Only requires two minutes of soaking in water to activate. Outperforms the competition by having an increased evaporative surface area, keeping you cooler. Machine washable.