How long can a stainless steel lunch box keep warm？

　　Most stainless steel lunchboxes cannot go into the microwave to heat food because stainless steel is not a conductive material for microwaves, which can lead to uneven heating or sparks. If you need to use a microwave to heat food, it is recommended to choose a plastic or glass lunch box that is suitable for microwaves.

　　Stainless steel lunchboxes can generally keep food warm for 2-4 hours, but the exact holding time also depends on factors such as the temperature of the food and the ambient temperature. It is recommended to consume the food as soon as possible to maintain its temperature and flavor. If you need to keep the food warm for a longer period of time, you can consider choosing an insulated pot or an insulated lunch box with better heat preservation performance.