Polymer embedded fabric holds the water and keeps you cool as the water evaporates and remains hydrated for several hours. 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. Hyperkewl® polymer-embedded fabric uses safe and natural method to keep you cool. Evaporative-cooling process. Outperforms competition by keeping you cooler for longer due to the larger evaporative surface area. Quick two-minute activation - Remains hydrated for up to 10 hours.