Yes Usually, the insulation time of insulated lunch boxes is three hours, and a few with good quality will reach five hours. In hot summer, the temperature of the insulated lunch box will be longer, which can last for more than six hours. In the case of high temperature, food will change qualitatively, and it will taste bad if it is kept in an insulated lunch box for a long time. It is necessary to master the heat preservation time. In the cold winter, the insulation time of the insulated lunch box will be shortened, so pay attention to it when using it.