Personalized Happy 100 Days Of School T-Shirt. The Happy 100 Days Of School design features playful illustrations and vibrant colors that will surely bring a smile to your child's face. It's a fun and cheerful way to commemorate this special milestone in their educational journey. Whether they're wearing it to school or for a special celebration, our apparel will make them feel proud and excited about their accomplishments. 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.