Flat diapers are the traditional square diapers used by generations of families.  They are the most simple style of diaper and a very economical option.  As babies grow and require more absorbency, just add more layers of flat diapers or add a doubler.  They also make great inserts and doublers in other diapers!  Flats have an even number of layers of fabric throughout.  They can be closed with a Snappi or a diaper pin, and folded in a number of ways, or folded like a prefold and laid flat in a wrap style cover. A cover is required.