Firstly, the primary purpose of a raincoat is to keep children dry during unexpected downpours. A good-quality raincoat should be made from waterproof or water-resistant materials to ensure that rainwater does not seep through. Modern technology has provided us with a range of materials, including Gore-Tex, nylon, and PVC, which not only repel water but also allow air to circulate, preventing the child from overheating while playing outside.