TIME LOCK / Food container

In Korea, almost all families tend to make side dishes as much as eating two or three times, put them in airtight containers and take as much as they can eat for one meal.
They occasionally keep food ingredients in those containers and put them in refrigerators. Because of this, people often don’t know for how long they have kept them. To solve such a problem, some people write the date of keeping at the containers.
For time lock airtight containers, however, people don’t have to write such dates. They can check the date when they started to keep food by turning a time circle.