All-In-One is the combination of waterproof PUL (outer layer) and cloth - usually cotton or bamboo - sewn together in one piece. There is no stuffing involved. It is the closest to disposables. Some AIOs take a bit longer to dry because they're thickly together but there are a lot of AIOs in our store that are made of layers that can be flapped around in the wash/dry, making the dry time shorter. This type is most convenience to use especially for day care providers and babysitters.