Covers and Shorties
Diaper covers are one size fits all and have an athletic mesh lining that is quick drying so that you can reuse a cover for more than one diaper change.
Fleece shorties are great to use at night as an extra leak guard. They are roomy enough to fit over bulky diapers.
Sizes for Fleece shorties
Pictured is my little guy in a Xlarge. He is 27 pounds and is 27 months old. I can still squeeze him into a medium soaker but it doesn't cover the top of the diaper fully. Hope that helps with figuring out sizes.