I needed a boot that would keep my sons feet warm while he's riding in the pack on cold or snowy days. These work perfectly, and are easy to get on over his socks. They are not designed for walking children to use outside, but are great for the pre-walkers or trips where your child will be in the pack the whole time. My son wears a size 4 shoe, and the 12-18month boot fit perfectly (they claim its size 4.5-6, so I would agree with other reviewers that its probably running a little small)