Simply add ice and a little cold water for your perfect ice bag. Through restricting blood flow, the ice pack decreases swelling, reduces muscle spasms and importantly reduces pain. Ice therapy can be used for chronic conditions such as arthritis, migraines and dermatitis as well as acute injuries such as sprains, strains and even for muscle recovery following a workout! Our pack stays cold for long periods of time and does not leak! Simply add warm water (not exceeding 131 ?F (55 ?C)) and you have your hot pack ready to go. Heat therapy helps to relax and loosen tissues, stimulating blood flow. Heat therapy can greatly improve symptoms in conditions such as arthritis, headaches / migraines, fibromyalgia, menstrual pain / cramps, spasms, bursitis and stiff necks / backs. Our pack retains heat for long periods allowing for fantastic symptom relief.