Keep Food & Drinks Cold With OUTXE Cooler Backpack, keep cold and fresh for 18 hours. Great for lunch box and outdoor activities - Keep Food Fresh & Drinks Cold Perfect for daily use in lunch boxes, bento boxes, and coolers. Ideal for work, school, picnics, hikes, fishing, and more - Keep Breastmilk FreshBring back fresh breast milk for your baby to grow better. No longer need to carry multiple backpacks - Save Space4 slim ice packs (6.5 x 4.3 x 0.5) will fit in just about any lunch box or coolers that you can think of and takes up less food or drink space - Reusable Not like ice, OUTXE ice packs dont make a mess as they thaw and will stay frozen for longer. sandwiches and other food items dont get ruined when ice packs start melting - Easy Clean Just add water and stir to turn into a gel, freeze ice packs the night before use. Just rinse them and pop them back in the freezer after use, ready for next time