Helly Hansen Fleece Pullover Henley Sweatshirt

Size 16 yrs. So the official size on this piece is 16 yrs as shown on label, but I’m a woman’s size small and it fits nicely. So I’m putting this an S. It’s a loose fit. There are two black internal plastic things that I can’t remember what they’re for as shown in pic. If anyone knows what they’re for, lmk!!