If a container has a doorway at one side, then why not to make one more door from the second side. 20 ft container with this solution is almost DUOCON container, but it is more correct to say that this is a standard container of 20 feet with two doors; and according to the classification of containers it is a 20 foot DOUBLE DOOR container. Its second door serves as a factor of the best placement of the goods in opinion of many cargo owners.