Zubels 100% Cotton Boys Whale Graphic Knit Sweater Navy Blue ? Size 12-18 Months

Boys knit sweater by Zubels. 100% cotton. Light blue and gray trim accent. The left sleeve has 2 darkened/stained areas. Its only visible in certain lighting (refer to area pointed out in a close up). No holes or blemishes otherwise. Two buttons at the neckline for ease in taking on/off. There is no size tag. I have this held up to another sweater that is 6-12 months. This sweater listed is larger then the 6-12 month. My best guess is that its a size 12-18 months. Please refer to the measurements provided to determine accurate fit.