This bag folds flat and can be kept closed bag-type clips to back.
The bag has a vertical partition cutting the volume by 2/3 1/3 so that everything does not mix. You can choose to open it in part: déclipant in only two clips of 4 you can fall open only 1/3 or 2/3 of the bag.
Note that the bag has Velcro underneath to the real estate in the trunk and two handles to be used in carrying bag.
My wife me "borrow" regularly, tell you if it is convenient ;-)