Check with your preschool, but in our case, we need to pack a lunch and two snacks, and there isn’t access to a microwave, so everything needs to be cold. If we have a hot component, we use the Omiebox bento box. For all cold lunches, we use a Bentgo lunchbox as well as small Bentgo ice packs. I layer two of the thin ice packs in the bottom of the lunchbox. Then, I add the Bentgo box and our two snacks on top. Don’t forget to pack a fork and spoon!