This hat looks like the engineer hat that they sell at "Day Out with Thomas" but without the badge indicating that's where it's from.  The elastic in the back and strong and stretches comfortably.  I bought this for my 2 year old and it's a little big but we were able to fold the back down and he thinks it's great.  As a bonus that hat is big enough that my 5 year old can fit it on her head so I know my son will gets lots of years use out of it.