Traveling with a child would need you to bring all the necessary things that he needs: baby diapers, milk, powder, an adjustment of garments, and lots of even more. Loading every little thing up in a sling bag would be too heavy when you have the child in the other arm. As a carrying parent, you would need to release you hands as long as feasible to be able to care for your child. That is why a knapsack nappy bag is far better compared to other bag to keep child's basics.