USB Controlled Heating：This lunch bag can be heated with a charging treasure and controlled by a button (Button can change three colors and must be pressed for more than 3 seconds). Warm and Cold Compartments：This lunch bag can be insulated and kept cold, making it ideal for lunch bags, picnic bags.（Heating temperature range is 40-50-60） High Quality Material：The exterior is durable and waterproof fabric with non-toxic aluminum foil inside, ideal for packaging food and lunch containers. Safe heating：This lunch bag is heated by a safe heated film. Even in wet conditions, you don't have to worry about safety issues, you can still use it safely. The 10000 mAh mobile power supply can be used for 3.5-4 hours at maximum power. (Note: The maximum voltage used is 5V) Lunch Bag Guarantee：If you are not 100% satisfied with our lunch bag,we offer you refund or replacement. If you have any problem,please contact with us by email, we will solve it for you within 24 hours.