Personalized Big Bro Big Brother T-Shirt. Whether you're looking for a thoughtful gift for a new big brother or a cute outfit for siblings to wear together, our collection has something for everyone. Explore our range of matching sibling apparel and accessories today and make your next family event even more memorable. 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.