Personalized Kawaii Backpack 100 Days Smarter T-Shirt. T-Shirt - White with funny kawaii cartoon backpack with eyeglasses and giant pencil says I'm 100 Days Smarter. Cute 100 Days of School gift Everyone loves our Custom T-Shirts! 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.