A bag slightly bigger than the tk-4258, the tk-4278 is just big enough to carry your books in. Under the flap contains an assortment of pockets. One pocket is zippered and big enough to hold your papers and magazines and the other is perfect for smaller items. This bag also contains a very small compartment just for coins. There are also pockets for holding your cards and key rings for your keys. Don't forget the additional back pocket for your cards and keys secured with Velcro.