Personalized Irish 1st Birthday Shamrock T-Shirt. Cute it's my 1st birthday T-Shirt - White with green bulldozer and Irish shamrock clover for a little boy turning 1 in March. 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.