This is a huge made to order shoulder bag I have affectionately called the "suitcase" during its construction.
The body is about 15"wide and 13.5" tall. The flap brings the width to 18".
It has a gusseted pocket on the front. The interior compartments of the fully gusseted main body consist of a full divider and 2 large internal pockets, all having bound edges. Iron buckles.