He fits comfortably in 3t clothing and can get away with some 4t shirts. there you have it, good luck! Just buy from someone else, this isnt worth the headache. My favorite thing is the zip up part! Seller was fast as well, through prime. We tried going with cheaper versions from big box stores but they never fit right, and would leave terrible marks on his feet. So the functional part of the strap is only 11. Works as a warm beanie but headset not working after a full charge. It is a noticeable difference with my old headphones; although I dont think the old ones were specifically noise blocking, they did muffle noise while these AKGs do not. Perhaps having them backward is what caused the noise.