The Ecoposh Obv Newborn Aio (All-in-One) Cloth Diaper is designed to fit preemies and newborns ranging from 4 -12 pounds. The Ecoposh Obv Newborn Aio features a four layer thick snap-in insert. This diaper requires the use of a diaper cover, such as the Rumparooz Newborn Cover (sold separately).