[LUNCH BOX]: The single-layer lunch box has no thermal insulation layer, surrounding ambient temperature is colder, the warm holding time for hot food will be shorter in an hour. When the ambient temperature is 68, add hot water above 203 into lunch box for testing, the warm holding time is about 1 hour(Recommended for children over 3 years old) [WITH BUCKLE]: The lunch box adopts a fashionable short buckle design, can be easily fastened with one press. There are safety latches on both sides of the lunch box, no need to worry that the lunch box will loosen after locked buckle. [VENT HOLE]: Bento box for adult is designed with silicone sealing ring for improving the sealing performance. Bento box also adopts vent hole design. Press and hold the vent hole to seal. Open the upper vent hole before opening the cover. [WIDELY USED]: 900ml bento boxes has portable concealed double curved handle, not only suitable for going out to use, you can also use common tableware at home. The lunch box is suitable for office workers, students, people traveling, etc. [FOOD GRADE]: The inner layer of bento lunch box using high quality stainless steel material, mirror polished and easy to clean. The outer layer uses food grade PP material, which is light weight and high temperature resistant, safe and hygienic.