All-In-One (AIO)

An AIO is made of a waterproof outer layer and an absorbent inner layer. It is a complete diaper that does not require anything additional to make it functional. This diaper is most comparable to a disposable. It comes in velcro or snaps for size adjustment. The diapers can take a while to dry due to the fact that they can't be taken apart and have to be dried as a single unit.

Pocket Diaper

The pocket diaper consists of a waterproof outer layer with a pocket attached. You can stuff the pocket with either a prefold or insert(s) to create to make it absorbent. The absorbency of the diaper can be adjusted by how much you stuff the diaper or what you choose to stuff the diaper with.  These diapers dry fairly quickly because the absorbent layer is removed during washing creating two parts. 

Fitted Diaper

The fitted diaper uses velcro or snaps to close the diaper. This diaper is not waterproof it is meant for absorption only. A cover must be used with the fitted diaper.

Prefold Diaper

A prefold diaper is a flat diaper that is rectangular in shape. There are many ways to fold a prefold diaper. Depending on the fold you may need a snappi or pins to keep it in place. A cover must be used with the prefold diaper.

Diaper Cover

A diaper cover is put on over a fitted diaper or a prefold. It makes the diaper waterproof. The great thing about covers is that many do not need to we washed in the washer after each use. They may simple be wiped out and air dried between uses. The diaper cover is made with Velcro or snaps.  

Doubler

A doubler may be added to any diaper to increase absorbency.  They are often used during naps and at nighttime. 
 

Insert

An insert is placed inside the pocket of a pocket diaper or in the pocket of an AIO, if available. The insert may be any absorbent material, most often microterry or hemp. They come in a range of sizes. A prefold may also double as an insert.
 
Liners

A liner is placed inside the diaper to protect it. It aids in solid waste removal and can prevent stains on the diaper. The liner, if made of fleece, can act as a stay dry barrier between the baby and diaper.