As a cooling pack to cool affected areas with heat by refrigerating them in the refrigerator. Use them as a heat pack to warm up affected areas such as poor blood circulation. Both of them can be used repeatedly. It does not harden even after long periods of time cooling and is soft to use. When using it cool: Please use it in the freezer or refrigerator, and wrap it in a towel or other place. ◆Chill it in the freezer for more than 2 hours for a cooler feel. (When Warming Up) Heats up in the microwave (800 w). Place it horizontally in the stove, spread the gel inside evenly. Heat for 30 seconds. (When warming from freezing state, it will return to room temperature before heating) Medical device notification number 13B2X0023100046 Class I (General Medical Devices)