Reefer container keeps perishable goods cold or frozen and is capable of maintaining a wide range of temperature for frozen, chilled or warm cargo. This type of container has a refrigeration unit whereby power is provided by a motor generator when the container is on the move, by terminal when it is placed stationary on land or by the ship when it is on the board. Warm or cold air is supplied to the container through an air duct system which circulates all over the cargo before it goes back to the refrigeration unit. This goes on as long as the unit is in operation. The adjustable ventilation holes in the refrigeration unit helps to prevent spoilage to the living products(cargoes) as it expelled the warm toxic air which is produced by the living products from the container. There are some advanced reefer container which is computerized, thus enabling highly precise temperature control which ensures the preserving of the quality of living products at all times in this type of container.