School backpacks with a hard frame

Rigid frame

— the presence of a rigid frame in the product. For knapsacks (see "Type"), this feature is almost mandatory, among backpacks it is relatively rare, in bags it is not used at all. Anyway, the functions of the frame depend primarily on the type of product: in backpacks, it primarily protects the contents from shock and compression, in knapsacks it also maintains the optimal shape of the product from an orthopedic point of view.