Footbed fits well, but the ankle portion is very tight with little flexibility on the 4T-5T size. I bought these at the big "Bulls Eye" store and thought they'd be great, because so far, in every small size, they have been fantastic...but it turns out they just seem to make the toe-to-heel part larger, and left the cuff that covers the ankle the same size as the smaller toddler size.  Don't know why, but won't be buying these again until maybe we move into "big boy" and they account for growing bodies- not just feet!  By the way, my son is tall, thin-to-normal legs.  These would be quite restrictive on the average "fleshy" toddler.