My son is 4 year old and he is pretty tall. WE ordered the size that is supposedly good for 3-4 year old kids, but in reality it's very long and it's good for a 6 or 7 year old. I have to adjust it which is not fun. I am not returning it because there was no smaller size or that's what I understood and returning is such a hassle. I also agree with the person who wrote the chest muscles are too big and my son can't see the ground that well. But the arms' muscles are great. All in all, it's OK, we'll fix it. But I am tired of fixing costumes.