Personalized Penguin 1st Birthday Youth T-Shirt. Penguin holds a birthday balloon with a 1 on it. Cute on a onesie! Happy 1st b-day one year old! 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.