Personalized 100 Days Of School Party Long Sleeve T-Shirt. Celebrate the 100th Day Of School with this cute Long Sleeve T-Shirt - White elementary school collage for teacher or student. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL