1. Durable Material: The Lunch Ice Crystal Box is great for refrigeration. It contains dry ice crystal particles, which are coarse and have good expansion. 2. Convenient to Use: The ice crystals in the Ice Crystal Box expand as they absorb water and freeze. When you add water to it, don't fill it up, you need to reserve some space. 3. Use for A Long Time: When the Ice Pack for Cooler overflows with ice crystals when it expands, you can clean it and continue to use it. It can be used repeatedly, and the refrigeration effect is long. 4. Various Applications: The Freezer Ice Pack can be used not only in Food refrigeration, breast milk preservations, air conditioning fan ice crystals, nursing cooling but also in barbecues self-driving refrigerated transportations, etc. 5. Used for Lunch Bags: You need to use the Cooler Ice Pack after adding water, its ice crystal particles will swell with water. After puffing, it needs to be put in the refrigerator for about 2-4 hours before you can put it in a lunch bag.