The latest USB insulated lunch box launched by Thanko, Japan, allows you to take your lunch to the office in the morning and plug it into the USB port, so it will keep your lunch lovely and hot during this period. By noon, we'll have something hot to eat. From the picture, it is put two thin heating tablets inside, it seems that USB really can do anything.
This thing size 140x200x90mm, support USB 1.1, 2.0, the price of 1980 yen, about 140 yuan.