I have a been searching for an overnight solution for my 7 month old son for MONTHS. I thought I was going to have to give in and find an overnight disposable until I read the reviews for these covers. I paired it with an imagine fitted or nicki's fitting and it worked wonders, no leaks! They fit great. My son is long and lean and I think now about 17 or 18 lbs. The leg holes on the medium fit him wonderfully, maybe even slightly loose so plenty of room to grow into them. I was so happy to have him wake up the past 2 mornings with no leaks from 7pm-7am!