We wanted to keep it simple but know that our customers want choices! We have created two different types of Regular inserts to snap into the shell for everyday use. You can mix and match meeting all preferences and needs. Both insert types are super trim making the Best Bottom one size diapering system one of the trimmest cloth diapers around. We offer each of our Stay Dry and Hemp/Organic Cotton inserts in three different sizes. Sizing is approximate and will depend on size and shape of baby as well as how heavy of a wetter.