Minimize laundry with this two piece style. A comfy, absorbent inner and a water proof but breathable cover that can be used several times between washes.

Fitted diapers require a cover.  They are often more absorbent than a typical all in one or prefold, but require a cover so they do not wet the baby's clothes (and you!).  These diapers are good if you would like to use a cover a few times as well as for an overnight diaper.  For those that use prefolds and have issues with fit or leakage it is often a good alternative since you already own the covers.