Lightweight vest features our patent pending spinal cooling design that lowers weight and increases cooling efficiency. Vest and neck wrap can be used separately as needed or together for maximum cooling benefits. Add a Polar cooler to take your extra pack sets with you on-the-go. Features: Snug, Comfortable Fit: The outer shell of the fashion vest is constructed of 97% cotton and 3% spandex for a touch of stretch. Available in seven sizes to ensure a perfect fit. Fashionable And Discreet: The cooling vest is easy to put on with the zipper-pull front. The clean design has no logos or visible pack pockets. Wear the vest over clothing or discreetly underneath. Deluxe Fabric: The cooling vest shell is constructed of durable and machine washable 97% cotton and 3% spandex. The lightweight fabric is breathable and looks fantastic! Kool Max Cooling Packs: Kool Max frozen water-based cooling packs require access to a freezer and offer the highest level of cooling energy. These reusable packs deliver comfortable cooling for up to 3-4 hours. It takes more energy to charge these packs in a freezer and in return, the packs offer greater cooling energy than Cool58 cooling packs. (Please note: cooling times are estimates and will vary depending on climate, body metabolism and activity.) The different vest sizes include eight (8) to ten (10) 4.5" x 6" packs. See the size chart for more information. Insulated Pack Pockets: Packs fit into insulated pockets inside the cooling vest. The pockets are lined to protect the skin with insulated outer composite fabric to direct the cooling energy toward the body. Temperature may also be adjusted for comfort by increasing or decreasing the number of clothing layers beneath the vest or the number of packs used. Variable Weight: Weight may be adjusted by varying the number of cooling packs used. Need a lighter weight vest? You don't have to use all of the packs! The use of separate, individual packs allows the number of cooling packs used to be customized for each person's preference and size. Some people find that using just packs down the spine works well, resulting in a vest that weighs just 2 lbs.! Others prefer all of the packs. Our design allows many options! Patent Pending Spinal Cooling: Pack pockets are placed strategically down the spine for optimal cooling. (Patent pending design!) The location of desired cooling is easily controlled by which pack pockets are used. How do Kool Max water-based cooling packs work? Kool Max frozen water-based cooling packs require access to a freezer and offer the highest level of cooling energy. It takes more energy to charge these packs in a freezer and in return, the packs offer greater cooling energy than Cool58 cooling packs. These reusable packs deliver comfortable cooling for up to 3-4 hours. (Please note: cooling times are estimates and will vary depending on climate, body metabolism and activity.) Packs are non-toxic and non-flammable. Works in any climate - extreme heat and humidity are no problem! The cooling performance is not impacted by humidity or outside temperature. Polar Products Kool Max Men's Fashion Cooling Vest for Sizes S & M