It has the process of putting hot water to heat the container, then putting warm food inside, but it keeps it warm until the child eats it throughout the day. The child opens it relatively easily, sometimes when I have heated the food too much, the lid gets stuck and doesn't open easily. It has never leaked food, nor soups. It cleans very easily, but if food gets into the groove of the lid, it is a bit of a hassle to remove. One of the most successful purchases I have made. It is a bit expensive, but it is the second school year that the child has been using it and it is like new. So I didn't have to buy a thermos again. However, it needs to be hand washed and not put in the dishwasher. The only negative it has.