A school bag is a backpack that attaches to the back to carry school supplies, similar to a backpack or shoulder bag. School bags should be anatomically adapted to children. Bags are not attached to the arm, only to the back. Straps should be tightened during transport.
Today, schoolchildren often use backpacks instead of school bags. These are different from soft-bodied backpacks. The rigid body of the backpack protects both the child and the contents of the backpack, and the rigid back prevents the contents from pressing on the back of the child.