Our Adjustable Zipper Vest with Cool58 Phase Change Packs is a great choice when access to freezers is limited. We have three choices of pack sizes so you can choose the ideal weight for you. 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. Cool58 Cooling Packs: Cool58 cooling packs freeze solid at a moderate and comfortable temperature of 58° Fahrenheit, so they can be activated in a freezer, refrigerator, or even a bucket of ice water. (Please note: cooling times are estimates and will vary depending on climate, body metabolism and activity.) The vest includes four (4) Cool58 cooling pack strips. See "6. VARIABLE WEIGHT" below for more information on pack dimensions and weight. 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: 6" x 13" pack strips with 500g of cooling material; each pack weighs 1.1 lbs. for a total vest weight of just 5.5 lbs. (Not available for size S/M) How do Cool58 phase change cooling packs work?: Cool58 cooling packs freeze solid at a moderate and comfortable temperature of 58° Fahrenheit (14.4° Celsius), so they can be frozen in a freezer, refrigerator, or even a bucket of ice water. Once activated, these reusable packs deliver comfortable cooling for up to 3 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. Packs do not require a freezer! Packs can simply be submerged in ice water or placed in a refrigerator or freezer to activate. Easy to use - packs can be activated by simply submerging the packs into ice water for up to 20 minutes when access to freezers is not available. 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. 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: Khaki, Blue Size: S/M, M/L, L/XL, XL/2XL, 2XL/3XL Your choice of four (4) Cool58 cooling packs 6" x 13" packs with 500g of cooling material; each pack weighs 1.1 lbs. for a total vest weight of just 5.5 lbs. (Not available for size S/M) Polar Products Cool58 Phase Change Adjustable Front Zipper Cooling Vest for Sizes M/L, L/XL, XL/XXL & 2XL/3XL