Personalized Retro Rainbow World's Best Big Sister T-Shirt. Whether it’s for a birthday gift or just because, this stylish apparel is a great choice for any occasion. It’s designed for comfort and style, making it ideal for everyday wear or special family gatherings. Your big sister will feel extra special wearing this, reminding her of her important 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.