Personalized 4th Birthday Monster Truck Baby Sweatshirt. I'm Four! A red monster truck drives over the words. Great fourth birthday gift for your favorite 4 year old. Keep your little one warm and comfortable with this soft infant crew fleece sweatshirt. Made from a cozy cotton poly blend, this pullover offers just the right amount of warmth for cooler days without feeling bulky. The snap-tape neck closure makes dressing quick and easy, and the ribbed collar, cuffs, and hem provide a secure fit that moves with your baby. Durable stitching and side-seam construction help the sweatshirt maintain its shape and softness through repeated washing. Great for everyday wear, daycare, playtime, or layering during fall and winter, this fleece sweatshirt is a practical and comfortable essential for any baby wardrobe.