This is a handy thing to have if you pack lunches for your children. If your child is like mine, sometimes they don't eat all their lunch and you have to toss out items that they bring home because they were kept at room temperature all day. Well, this lunch bag stays cold from 7:30am to 3:30pm. All you do is place it in the freezer over night and then pack the lunch in the morning. The children actually like them too. While they do not have a great variety of colors they do have enough choices to choose from. This is a worthwhile investment. I plan to buy two more in the near future. I have tried knock off brands and they do NOT compare. In fact, the bag I bought is useless. Items may stay cold for an hour. It works nothing like the Packit. The Packit acts like a mini refrigerator and actually keeps the item cold. You are taking your chances with the knock off brand. If I had the receipt, I would take the knock off back to the store.