The total volume of the product. It can be indicated both with external pockets and without them (see "Compartments") — this is not critical in this case, because the capacity of the pockets is small and does not really affect the overall capacity. But the external compartment (see ibid.) is necessarily taken into account in the characteristics, since it accounts for a fairly significant part of the volume.
Larger capacity allows you to carry more items inside. On the other hand, for pupils of primary and secondary grades, capacious backpacks are not required, and a heavy load can be harmful to health and normal development. Therefore, the volume largely depends on the age category. Thus, the volume of backpacks (see "Type"), which were originally designed for the younger age group, rarely exceeds 20 liters, and in most cases is less than 15 liters. The same applies to bags, but in their case it is more likely due to design features, and the volume is generally larger — up to 29 liters. Backpacks are the most voluminous — among them models of 25 liters are not uncommon, and in some
the volume exceeds 30 liters. However, the choice of volume depends not only on the age category, but also on the expected amount of cargo. So, a high school student may not need a roomy backpack if the school has lockers and textbooks are mostly stored there.
Empty weight. This parameter has a dual meaning. On the one hand, the lower the own weight of a backpack, bag or knapsack, the less load will be on the shoulders of the child with the same weight of the load. On the other hand, with the same materials, a lighter product is also thinner and, accordingly, less durable.
