White Original RPCM Cooling Vest is a dry bio-based cooling system that uses an exclusive technology with patented "green" phase change material. It helps in keeping body temperature at normal when in extreme temps places using high garments to prevent the person from heat stress or stroke. These cooling packs last up to 2.5 hours at 59 degrees F and are also rechargeable in just a few minutes. It remains at 59 degrees F, even in the most extreme hot environments and it will never over cool. Shorter than other vests so best worn undergarments. PCM cool packs are non-toxic and do not contain hazardous ingredients or chemicals. When merged in ice water, these packs only takes 20 minutes to recharge. Weighs less than 5 pounds and does not contain any harmful ingredients so it is safe and hassle-free to use. Has longer cool time than gel or ice-cooled vests. Comes with adjustable side elastic straps ideal for any body size. Perfect for hunters, construction workers, and those with Multiple Sclerosis.