Personalized 100 Days Of School 100 Days Of Cool T-Shirt. Show off your child's achievement with this adorable 100 Days Of School 100 Days Of Cool design apparel. Perfect for celebrating the milestone of completing 100 days of school, this cute and happy design is sure to bring a smile to anyone's face. 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.