Personalized That Was Pretty Cool 100 Days Of School T-Shirt. This 100 Days of School design is an ideal gift for your little one or their friends who are also celebrating this milestone. It's a fantastic keepsake that will bring back joyful memories for years to come. So, dress up your little achiever in our cute and happy design and let them shine on their special day! 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.