Trolley bag is a type of bag that has risen in recent years. It refers to a bag that is similar in shape to a trolley suitcase and that is lighter and suitable for children. Unlike the bags that children usually use, the trolley bag adds a drawbar and a small wheel, so that when the children face books stacked in the mountains, they don't have to frown, just drag and drop. And now the lever design of many lever bags is detachable. When the book is not a lot, the child can remove the lever, when the ordinary bag is directly on the body.