I ordered the headphones to take our newborn to the racetrack. The sizing is spot on for babies with room for growth. When I put them on my 1 month old I had to extend them a little so they will work for even smaller babies. In response to a man who reviewed them and said they do not cancel out noises...they do! When the noise goes over a certain decibel it absolutely cancels it out while still allowing you to interact with your child. worth the money to protect my little guy. i contacted the company directly with some questions via chat and they were accommodating and informative with fast results. A++ service.