I bought a set of these for my 8 month old grandson because I wanted a "base layer" to go under his fleece sleeper when I pick him up in the morning. It's usually in the high 20's to mid 30's outside and this works great for our walk out to the cold car for the drive to and from his home. I wasn't sure how to keep him warm since the new guidelines are to not use heavy weight winter coats in infant car seats -- this plus a blanket seems to work great and he's very comfortable. I know it's working because before I bought this I would get him home and his skin would actually feel cold to the touch - now he's nice and warm (not hot and sweaty - just comfortable warm). I don't know if this will shrink or not because I line dry them.