The pockets can be flattened by means of side straps.
This model has a lap belt but also a chest strap, useful to secure the bag when loaded.
I carry with me easily binders, notebooks and sorters large (24x32), a netbook and all the usual hurly-burly of a one liter bottle ... and there is still room!
The quality of the lining is poor but otherwise I am very satisfied, especially for the current price.