These cold therapy ice packs for injuries do NOT need a freezer to become ice cold. All you have to do is squeeze the center of the flexible ice pack and it will instantly become as cold as regular ice. This effect will last long enough to reduce your swelling and inflammation. Thick medical grade plastic lining and strong seal prevents leaks or punctures. Convenience: keep a few of these formfitting gel pads in the freezer for immediate use when you need an ice pack. The non-toxic cooling gel pad is contained in a durable material preventing it from leaking or getting punctured. It can stand excessive use and will remain effective. This cold pack for knees is recommended by athletes, therapists, and mothers alike. Safe for everyone the icE pack consists of full soft silica gel, which keeps the ice pack flexible when frozen. Did you sprain your ankle while running? Are your muscles sore? Do you suffer from toothache or headache? Did you get burnt or bitten by an insect? This instant ice packs will reduce the swelling and the inflammation, provide you with pain relief and speed up your recovery. Our ice pack is soft, durable and split-resistant as well, which can be chilled in the fridge or heated in the microwave, served as an ice pack or a heating pad, while still remaining soft.