We have loved these wool covers since we got them for our baby as a newborn. This OS+ is very roomy for my 15 month old to grow into for a long time. It is on the tightest setting. We love the trimness of the diapers with the snaps to get just the right fit. We use the covers with cotton prefolds and they look like the typical fluffy cloth diaper under clothing, but don't have to size up quite as much as you do with other wool covers because it isn't as thick and bulky. Wish we would have not been intimidated by wool for our other 4 babies.