PATENTED DESIGN: Innovative thermal pouches inside the pack resist body and outside temperature for long lasting therapy. Up to 3 hours of cold therapy or 2 hours of hot therapy per session REUSABLE, LONG LASTING ICE & HEAT: Freeze pack for ice or microwave for heat. Can be used over and over for first aid, injuries and food at home or on the go MULTIPURPOSE HOT COLD PACKS: Use on nearly any area of the body, including shoulder, upper/lower back, neck, elbow, wrist, leg, knee, ankle, foot, jaw, and more. For pain, sprains, strains, tears, and other injuries. Icing is best for pain relief, reducing swelling/ inflammation, and injury recovery. Heat is best for stiff joints, sore muscles, and relaxation SAFE FOR FOOD: Slim, long lasting pack keeps food and drinks inside coolers, lunchboxes, lunch bags, and grocery totes cold. Can also be used to chill insulin and breast milk. Use at work, school, in the car, and outdoors