Personalized Big Sis Owl Girls Sister Announcement T-Shirt. Cute Sister owl has a fun retro look in pink, brown and orange, and comes on a sibling T-Shirt - White gift for the new Big Sis. 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.