Personalized Happy 100 Days Of School T-Shirt. Show off your school spirit with our Happy 100 Days Of School apparel. Whether you're wearing it in the classroom or out and about, this design is a fun and cheerful way to celebrate this educational milestone. Grab yours today and make every day at school a little bit brighter! 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.