Personalized Rainbow World's Best Grandma T-Shirt. This collection is not just a gift; it is a heartfelt expression of love for grandmothers everywhere. Perfect for any occasion, the Rainbow World's Best Grandma apparel is a thoughtful way to honor the role of a grandmother, or "nana," in the family. Show your appreciation with this cute and meaningful apparel that embodies the spirit of family and the joy of being a grandmother. 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.