Personalized Retro Rainbow World's Best Big Sister T-Shirt. This delightful design not only celebrates the big sister but also emphasizes the joy of sisterhood. With its eye-catching rainbow theme, it’s a fun addition to any wardrobe. Gift it to the best sister ever and watch her beam with pride as she embraces her role in the family! 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.