The sides of the bag expand, making it quite large. If you're on the run and are accumulating a lot of things along the way, this would be a great bag because of the expandable sides and the fact that you don't have to worry about a zipper.
This bag is fabulous! I own a small collection of city bags and wanted to mix it up for a trip with the family to Europe. I found the shopper and have not used one of my city bags in three weeks. Great for loads of stuff and fits over the shoulder even with a coat.