On all but the economy Thermoboxes, Thermoboxes have stepped joints between lid and box to give optimum sealing.
Stepped junctions between lid and box greatly reduce the ingress of ambient temperature air during box movement. This is essential for transporting hot or frozen food.
Reduced ingress of ambient temperature air greatly increase Thermoboxes capability to hold products at high or low temperatures during transport.
For chilled food transport compromises can be made when purchasing Thermoboxes, because the ambient temperature might be quite close to that of the product being carried in the box. For Hot or Frozen food transport is that the lid locks shut when the box is closed.
