Personalized Happy 100 Days Of School T-Shirt. Whether your child is celebrating their 100th day of school at home or in the classroom, our Happy 100 Days Of School design apparel is a must-have. It's not only a stylish addition to their wardrobe but also a special keepsake that they can cherish for years to come. Get your hands on this cute design today and make your child's 100th day of school even more memorable! 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.