Personalized Cupcake First Birthday T-Shirt. Our 1st birthday outfit for boys is the perfect choice for your little man's special day. With a stylish design and soft fabric, this outfit will keep him looking and feeling great throughout the birthday celebration. Whether it's a cake smash photoshoot or a birthday party, this outfit is sure to impress. Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.