Personalized Submarine 1st Birthday Adult Sweatshirt. THINGS ARE LOOKING UP 1st birthday Adult Sweatshirt - White with big number 1, colorful submarine, little deep sea explorer in the porthole and bright fish with bubbles. Stay warm and stylish with this classic adult sweatshirt, perfect for everyday comfort. Crafted from soft, durable fabric, it features a relaxed fit for added coziness. Whether you’re lounging at home, running errands, or enjoying outdoor activities, this versatile sweatshirt is a wardrobe essential for any season.