The Champion 5034 6-inch by 10-inch Therma-Kool Hot-Cold Pack is a unique gel in a soft but sturdy plastic envelope, designed for use as a hot or cold compress. When prepared as directed, it is ready for use in minutes. As COLD compress: Store in the freezer unit of refrigerator for ready use. Place Therma-Kool¨ in soft outer cover before applying to the affected area. As HOT compress: Compress can either be micro waved or heated by immersion in hot water. Place Therma-Kool¨ in soft outer cover before applying to the affected area. For continuous hot or cold application, use 2 or 3 compresses in rotation.