Efficient Cooling: Enhanced by coarse ice crystal particles that expand when water is added, delivering extended cold storage and steady cooling to keep food and beverages fresh. Durable and Reusable: Thickened PE material resists breakage, ensuring reliable performance for repeated longterm use in lunch boxes. Portable and Lightweight: Compact size and light weight allow easy sliding into backpacks or lunch bags, maintaining portability while keeping meals cool. Easy to Use: Add water to initiate ice crystal expansion, then freeze for about 2 to 4 hours to maintain low temperatures in your lunch box. Practical Uses: Office or school lunches: place in lunch box to keep meals and drinks fresh until mealtime. Outdoor activities: suitable for picnics, road trips, or park outings to preserve snacks and beverages. Gym, travel, or commuting: lightweight cooling for snacks or drinks in gym bags or travel totes.