I'm working on diaper covers for summer for our little girl.
We cloth diaper and I like to use wool covers because they are the most breathable and coolest option. She gets terrible rashes if she wears disposable diapers when it's hot outside...and even if she's wearing some polyester types of cloth diapers.
She seems to do best with the simplest cotton diapers, and wool covers.
The wool gets washed with lanolin (from sheeps wool naturally, but can be removed during processing...). Lanolin makes the wool sort of waterproof, and it's also self cleaning.
There is a long chemical explanation for this, but I'll just give the very simple one. Urea from baby pee, mixes with lanolin to form a type of soap. Remember fight club... lye + fat = soap... well... lanolin + pee = soap :) and..they're waterproof-ish
This is the large size... on a 11 month old girl.. very tall, very thin... They're quite baggy and are fitting over our bulkiest prefold diapers. The fit is nice this way in my opinion...they'll fit her for a long time.