Fit Lunch Bags: The Cooler Ice Pack is used by refilling it with water. When water is added, the ice crystal particles expand. After expansion, place the pack in the refrigerator for about 2 4 hours before packing it into a lunch bag. Reliable Material: The Ice Packs contain coarse, expandable dry ice crystal particles, which deliver a strong cold storage effect. Use Simply: When adding water to the Ice Crystal Box, do not fill it to the . Leave some space for expansion, because the ice crystals expand as they absorb water and freeze. Used Repeatedly: The Ice Pack for Cooler can be washed and reused for extended cold storage. It expands with ice crystals as part of the cooling process. Practical use scenarios: Everyday lunches: Keep perishable foods and drinks cold for school or work. Picnics and outings: Maintain freshness of snacks and beverages during outdoor activities. Travel and commuting: Help keep items cool during trips or long drives.