Personalized Happy 100th Days Of School T-Shirt. Celebrate a major milestone with our Happy 100th Days Of School apparel! Designed specifically for this special occasion, our cute and cheerful 100 Days Of School design will add a touch of joy to your celebration. Whether you're a student, teacher, or proud parent, our apparel is perfect for commemorating this milestone in style. 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.