diaper change. Prefolds typically have 4 to 6 layers of material in the center and 2 to 4 layers on the edges. Shaped diapers – Shaped diapers resemble a prefold except, instead of the square shape, they are a triangular, T-shaped, X-shaped, or Y-shaped. They are not commonly used today as contour diapers have generally replaced them. Even so, prefolds (the rectangle shape) remain the most popular pre-folded diaper of the three (prefolds, shaped diapers, and contours). Contours – Contoured diapers are much like a shaped diaper or prefold except they are cut and sewn into a general hourglass shape. This is done so that no folding is required before they are ready to be used as a diaper - and also to reduce bulkiness. Fitteds – Fitted diapers are hourglass-shaped absorbent diapers that have elastic at the legs in order to better contain feces and urine. They usually also have a built in closure - such as velcro or snaps - that is used to secure the diaper onto the baby. There are several subtypes of fitted diapers including closureless fitteds (those that lack velcro or snaps), prefitteds (fitteds made from pre-fold diapers), and pocket fitteds (pocket diapers that use absorbent materials for all the layers instead of wicking or waterproof materials). Fitteds are popular today, particularly for use overnight, when a diaper capable of holding more urine without leaking is needed. Pocket diapers – Pocket diapers are hourglass-shaped and have closures to secure them onto the baby (generally snaps or velcro). They consist of a waterproof outer layer and an inner layer that are sewn together on three sides to create a pocket. The inner layer may be made of a moisture-wicking material or an absorbent material. The pocket is then stuffed with absorbent insert that can be customized based on the absorbency level required for each baby. The most common inserts are made of microfiber, bamboo or charcoal bamboo. One subtype of pocket diapers is the sleeve diaper, which is sewn only on two sides instead of three so that the pocket may be accessed from both the front and back of the diaper. All-in-one diaper – An all in one (AIO) diaper consists of a waterproof outer layer sewn together with absorbent material on the inside. There may also be an additional inner layer of moisture-wicking material. All-in-ones are hourglass-shaped and have a velcro, snap, or