The Chill-Its 6667 Wet Evaporative Cooling Vest is made with a lightweight PVA material that provides immediate cooling relief to the core area. The lightweight construction is designed with breathable mesh panel siding making it more comfortable than other wet evaporative vests that can be heavy to wear. A front zipper offers an easy on\/off, customized fit. For best results, we recommend this body cooling vest be worn over a t-shirt and not covered by other clothing. In order to activate, simply run under water and wring out, no ice or refrigeration is needed. The PVA material is super evaporative and feels cooler than ambient air, keeping you feeling cool and comfortable for hours. Machine wash as needed and hang dry for longest life, the vest will stiffen as it dries. All PVA materials dry stiff, to reactivate and soften, run under water. Great for construction, landscaping, roofing, or anybody working in the heat.