Personalized 3rd Birthday Monkey Youth T-Shirt. he happy birthday monkey motif is a cheerful way to commemorate this special milestone in your child's life. Let your little wild one stand out with our unique and cute birthday accessories. 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.