The ColdStar all-purpose hot and cold therapy gel pack is ideal for recurring hot and cold therapy needs. ColdStar can be used as a heat pack. Microwave it in the oven for heat therapy. Place it in the freezer and it becomes a reusable ice pack. The soft freeze gel stays flexible when frozen, which allows the cold pack to conform to the contours of the injured area. ColdStar cryotherapy gel packs are ideal for first aid kits.