Personalized Tibetan Mastiff Dad (Worlds Best) Dog Breed Baby Bib. Fun worlds best tibetan mastiff dad dog breed gift. Our Baby Bib is rated high in convenience and durability and with a variety of fashionable colors, your baby can be trendy. Mix and match to any outfit. 100% cotton ring spun combed heather colors are cotton-poly. Width 7.75", Length 11.75"