This is one of the oldest designs in my collection. Some things just don't need any change.
The bag takes a different shape depending on what you want to carry. From rectangular (books) to triangular (onigiri).
Closure is with press-buttons and the bag comes with a detachable shoulder strap. Three inside pockets.
Dimensions: 40 x 28 x 10 cm
Similar but a shoulder bag is: Amos