St Patricks Day Birthday Tshirt Happy Birthday to Me Solid colors: 100% Cotton; Heather Grey: 90% Cotton, 10% Polyester; All Other Heathers: 50% Cotton, 50% Polyester Imported Machine wash cold with like colors, dry low heat It's your St. Patrick's Day birthday, so celebrate and let the world celebrate with you! St Pat's birthday tee from Leprechaun Gifts. A circle of shamrocks on an Irish green birthday t-shirt design. Lightweight, Classic fit, Double-needle sleeve and bottom hem