Used Very Good Condition baby rashguard swimsuit with long sleeves. The Jessica Simpson label is wearing off but that’s what it used to say! I can’t remember what size it is, but I’ve put a a ruffle Butts 6-12 month suit underneath. The neck is narrower but the arms are longer. I’m calling it 6-months. This was my daughters first suit and we probably put her in it from 3 to 13 months.