Backpack-carrying "Classic" and "Light" are identical in design. The straps of the backpack can be worn behind the back only in parallel.
Convenient for those who are planning to use a backpack for the first time. They differ only in the presence of a pocket on the back (Classic) instead of a mesh (Light). The straps of the "Smart" backpack are specially shaped for comfortable wearing, crossed on the back.
Due to the fact that the straps are not thick, no thickness is formed at the intersection of the straps on the back, which is especially convenient for wearing such a backpack under a slingokurt.