Personalized Blast Off 3rd Birthday T-Shirt. BLAST OFF IT'S MY 3rd BIRTHDAY T-Shirt - White with cute astronaut and stars. 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.