Our best-selling cooling vest! The lightweight Adjustable Zipper Vest with 4.5" x 6" Kool Max Packs efficiently and effectively cools the body in any environment, under or over clothes. Additional pack sets are offered at a special discount when purchased with the vest! Your choice of an extra set of Cool58 58° Fahrenheit phase change packs, which are ideal when freezers aren't available, or a set of Kool Max frozen water-based packs. You may want to order a set of each type of pack for flexibility on-the-go! See the full comparison of cooling pack technologies below in "How does it work?" Features: Adjustable, Custom Fit: It is important for cooling vests to fit snug to the body for optimal cooling. This cooling vest has adjustable hook and loop straps at the chest, waist and shoulders for a snug, comfortable and customized fit. Convenient And Easy To Wear: Once the cooling vest has been adjusted for size, it is easy to put on every time with the zipper-pull front. The clean design (with no logos or visible pack pockets!) is available in several sizes. Wear the vest over clothing or discreetly underneath. Comfortable 100% Cotton: The cooling vest shell is constructed of durable and machine washable 100% cotton twill. 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 five (5) to twelve (12) 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 have a comfortable all-cotton fabric to protect the skin and an 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 three packs down the spine works well, resulting in a vest that weighs just 1.5 lbs.! Others prefer all of the packs except the two on the upper chest. 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 depending on environment, activity, and personal metabolism. (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. Specifications: One (1) 100% cotton cooling vest Simple and unisex design with a zipper-pull front. Size is adjustable with hook and loop closures at the chest, waist, and shoulders for a snug, comfortable and customized fit. Packs fit into insulated pockets inside the vest. The pockets have a comfortable all-cotton fabric to protect the skin and an insulated outer composite fabric to direct the cooling energy toward the body. Control the weight by varying the number of packs used. Discreet: can be worn over or beneath clothing. Colors: Blue, Khaki, Light Blue, Pink Sizes: XS/S, S/M, M/L, L/XL, XL/2XL, 2XL/3XL Five (5) to twelve (12) 4.5" x 6" Kool Max cooling packs Size XS/S holds five (5) packs Size S/M holds eight (8) packs Size M/L holds nine (9) packs Size L/XL holds eleven (11) packs Sizes XL/2XL and 2XL/3XL hold twelve (12) packs Polar Products Kool Max Adjustable Front Zipper Cooling Vest for Size S/M