Personalized Irish Shamrock Green Text Youth T-Shirt. A green shamrock made from the word Irish and small shamrocks is a unique gift design for St. Patrick's Day and Celtic festivals. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.