The Phase Change Poncho Vest (PCV) is adjustable at the sides and shoulders. One size fits most. Available in Khaki. Phase Change Cooling Packs deliver a constant temperature of 58 degrees Fahrenheit for three (3) hours. Resuable, non-toxic and non-flammable. Packs do not require a freezer! Can be chilled in ice water; refrigerator or freezer optional. The cooling performance is not impacted by humidity or outside temperature. Includes a set of four (4) segmented packs. Get an extra set of packs for a great value! Keep in the freezer or a cooler, ready to use. 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. Unisex design adjusts at the sides with hook and loop tabs. May be worn over or beneath clothing.