I was amazed that the hot soup or miso soup I put in in the morning stayed warm until lunchtime. I also thought it was amazing that it didn't spoil even after being left at room temperature for two days in the winter (just my personal experience). I used them for about a month, but I'm selling both because my new job has a company cafeteria. OCTAS stainless steel insulated lunch boxes, available in two sizes, making them convenient to carry. * Direct pickup is also possible in southern Ibaraki Prefecture, such as Kamisu, Kashima, Itako, Inashiki, and Hokota. * If you prefer shipping, please comment with your delivery area, and I will adjust the price to include shipping costs (+770-1200 yen). - Model: OCTAS 18, 22 - Material: Stainless steel - Function: Heat retention - Size: 18: Diameter 160 x Height 130mm, 22: Diameter 160 x Height 255mm - Capacity: 18: 0.5L, 22: 0.6L Thank you for looking. Shipping will be via Japan Post, size 100-160 (subject to change).