Personalized 3rd Birthday Look Whos Three T-Shirt. Whether you're planning a big birthday bash or a small family gathering, this 3rd birthday design is sure to bring a smile to everyone's face. Made from high-quality materials, this design is comfortable for kids to wear all day long while they enjoy their special day. 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.