Personalized Shamrock Irish Flag T-Shirt. This colorful Irish flag logo with green shamrock clover is a lovely gift for any Irish friend for St. Patrick's Day. It comes on a holiday T-Shirt - White. 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.