All-In-One DiapersAll-in-one diapers (or AIO’s) are a one piece diapering system, the closest resembling disposable diapers. An AIO is basically a fitted diaper and waterproof outer layer combined into a single diaper. The absorbent material is usually sewn into the diaper but can sometimes be detachable (also known as All-In-Two, AI2's). They fasten with either aplix (Velcro) or snaps and are definitely the easiest to use and a favorite for outings, babysitters and Daddy’s. They do take longer to dry and do not offer much customizing of absorbency other than adding a doubler. They also come in various colors and prints.