All In One (AIO)’s are fitted diapers that have a waterproof outer layer, which usually consists of fabric that has a PUL (polyurethane) backing. The inner layer typically consists of cotton, hemp or microfiber. The outer waterproof shell and the inner absorbent material are all sewn together. There is no stuffing or folding required with an AIO, simply remove it out from the drawer and put it straight onto baby! These are the closest in similarity to disposable diapers since they are a one-piece diapering system. Often an AIO diaper will take longer to dry then diapers with removable microfiber cores. Due to its simplicity of use, this is a great option to have on hand for babysitters, daycares, grandparents or any other caregiver that may not be familiar with cloth diapers.