Cooler backpacks with multilayered insulation have an outer layer, a lining, and a middle layer. The space between these two layers is filled with dense foam that prevents heat from coming through the outer layer reaching the contents of the water cooler backpack. They have a strap that makes it very convenient to hoist on to your back and carry it to wherever you are going.
This backpack needs to be packed properly to ensure its effectiveness. A layer of ice is added after you have stacked what you want to carry with the heaviest items at the bottom. A further layer of ice is added and then other materials that you want to be cool when you use them are added, and ice again added to the top, before you close the back pack. It can always help if the items you want to carry are frozen before they are put in the backpack.