I'm so glad I checked to see whether Amazon had this Fire Fighter suit.  Other stores have the same suit for a higher price.  My son will be four in a couple of months.  The 4-6 is perfect, giving him room to grow.  We don't need to roll up the sleeves on the jacket, but it is still large enough to allow for growth.  We rolled up the pant legs, but that doesn't seem to be a problem for walking (or running!). Everything is sturdy -- the material, the clasps, the helmet (sturdier than others I've seen).  I love that there is reflection tape, pockets, elbow and knee "pads".  We are very pleased!