The locking device is similar to that of a pill bottle. When opposite sides are pushed together it allows the top to unscrew.
The user opens the container, soaks the microfiber pads with water, lines them along the inside between the dividers, places the rubber gaskets on each end of the aluminum insert for an airtight seal, puts the insert with the gasket in place into the ribbed bottom, places the food inside, and finally screws the lid back on until they hear repeated clicks. At that point, evaporation will begin to take place and the aluminum insert will conduct the cold feeling of the evaporation to the food preserving it for a longer period of time.