【Brand New, Unopened】 Neck Ice Pack Size: L How to Use: ① It can cool automatically if the temperature is 28°C (82°F) or below. Rapid cooling is also possible using a refrigerator, freezer, ice water, or cold water. ② Freezing and Cooling Times: Cooling time in ice water or cold water → Approximately 30 minutes Cooling time in the freezer → Approximately 20 minutes Duration (in a 28°C environment) → Approximately 1 hour to 1 hour and 30 minutes ※ This may vary depending on body temperature and the environment. ※ Cooling reaction will be slower in warm water during summer, so use water below 28°C (82°F).