Personalized 1st Birthday Submarine Toddler Sweatshirt. Cute 1st Birthday Submarine Toddler Sweatshirt - Chill has number 1 on the porthole for your child's undersea party. Keep your little one cozy and stylish with this soft and durable toddler sweatshirt. Designed for comfort and ease of movement, it features a classic fit with ribbed cuffs and hem for added warmth. Perfect for everyday wear, playtime, or chilly outings, this sweatshirt is made to withstand the adventures of an active toddler