All of the flaps have the same length. When closed, the inner flaps will meet at the center of the box, this provides a flat surface on the bottom and full protection on the top. Lastly, the outer flaps overlap by one inch or more.
The Partial Slotted Container is usually used when the length is considerably greater than the width, resulting in a long gap between the inner flaps. The sealed overlap helps to keep the outer flaps from pulling apart.