Awesome shirt. Been looking for something like this, most seem to be rash guards for swimming that are thick and have designs on them. This is perfect for our hot humid climate, my husband and I live in shirts like this. It’s runs a little large I think, my baby is 13 months in the 90th % and usually wears 18-24 month. I got the 24 month and it’s slightly on the larger size but it’s perfect because it fits him now just a little long on the arms and will last him a few months. I liked it so much I bought the adult version for myself.